• Geomechanics and Engineering
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• v.14 no.2
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• pp.161-174
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• 2018

The present study investigates the soil-structure interaction (SSI) effects on the seismic performance of smart base-isolated structures. The adopted control algorithm for tuning the control force plays a key role in successful implementation of such structures; however, in most studied carried out in the literature, these algorithms are designed without considering the SSI effect. Considering the SSI effects, a linear quadratic regulator (LQR) controller is employed to seismic control of a smart base-isolated structure. A particle swarm optimization (PSO) algorithm is used to tune the gain matrix of the controller in both cases without and with SSI effects. In order to conduct a parametric study, three types of soil, three well-known earthquakes and a vast range of period of the superstructure are considered for assessment the SSI effects on seismic control process of the smart-base isolated structure. The adopted controller is able to make a significant reduction in base displacement. However, any attempt to decrease the maximum base displacement results in slight increasing in superstructure accelerations. The maximum and RMS base displacements of the smart base-isolated structures in the case of considering SSI effects are more than the corresponding responses in the case of ignoring SSI effects. Overall, it is also observed that the maximum and RMS base displacements of the structure are increased by increasing the natural period of the superstructure. Furthermore, it can be concluded that the maximum and RMS superstructure accelerations are significant influenced by the frequency content of earthquake excitations and the natural frequency of the superstructure. The results show that the design of the controller is very influenced by the SSI effects. In addition, the simulation results demonstrate that the ignoring the SSI effect provides an unfavorable control system, which may lead to decline in the seismic performance of the smart-base isolated structure including the SSI effects.

• Journal of The Korean Association For Science Education
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• v.37 no.1
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• pp.181-192
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• 2017

This study aims to examine the educational effects of the SSI program using Digital Storytelling (DST) approaches. Since DST provides students opportunities to express their own opinions in the form of stories and to share learning outcomes through the web, we developed and implemented SSI program by adopting the concept of DST in order to produce synergistic effects on student learning. Twenty-four 9th graders who enthusiastically engaged in the DST-based SSI program participated in this study. The students responded to focus group interviews after the instruction, and all interviews were transcribed for analysis. The results indicated that the students became aware of socio-ethical perspectives of each SSI topic while searching and collecting data by themselves. They also felt the necessity to consider multiple perspectives around the issues by having discussions with group members. Second, pre-producing DST allowed students to negotiate to settle on a group discussion, and to use emotional contents that can lead viewers to have sympathy. In addition, while producing DST, students considered various factors such as design, soundtrack, visual effects, and screen composition in order to express their opinions and convey their messages more effectively. In the stage of sharing DST outcomes and receiving feedback, they realized new perspectives that they did not perceive in the previous production process, and to move them into an action for resolving the problems caused by SSI. This study showed the potentials of DST-based SSI instruction as a good strategy to support students' SSI engagement.

• Journal of The Korean Association For Science Education
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• v.37 no.3
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• pp.395-405
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• 2017

This study aims to investigate the effects of socioscientific issues (SSI) instruction on promoting college students' character and values as citizens, and to compare the effects based on the psychological factor - idiocentrism and allocentrism. Thirty-one college students who enrolled in the SSI course participated in this study. The SSI course provided the students with opportunities to explore various aspects of five topics, to express and share their own opinions, and to identify reasonable alternatives. The students with distinct tendencies were classified into two groups (i.e. idiocentric and allocentric groups) based on the personal value orientation scores before the instruction, and they responded to the questionnaire to examine their character and values as citizens before and after the instruction. The results showed that the students' social and moral compassion and socioscientific accountability improved significantly after the SSI course. The overall effects of the SSI program on students' character and values were not significantly different between two groups. However, the post-mean score of the allocentric group in socioscientific accountability was higher than the one of the idiocentric group. This study shows that SSI instruction could positively affect character development regardless of psychological tendencies, and could be implemented in the science classroom as a good instructional approach to integrating science education and character education.

• Computational Structural Engineering
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• v.6 no.2
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• pp.87-93
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• 1993

Recently it is recognized that the effects of structure-soil interaction(SSI) on the response of structures are important in the dynamic analysis of structures. In this study, theoretical and experimental investigations were performed to study the SSI effects(mainly inertial interaction) on the dynamic response of buildings utilizing the finite element foumulation. Theoretical studies were performed with two idealized buildings(stubby one and slender one) built on the homogeneous soil layer and having the small embedment ratio. Experimental investigations were also carried out for two buildings built on the pile foundation in Mexico City, experienced the 1985 Earthquake. The results of this study show that the SSI effects are significant on the response of structures due to the change of fundamental frequency and effective damping ratio, and that it is necessary to include the SSI effects on the dynamic analysis of structures.

• Journal of Korean Elementary Science Education
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• v.42 no.1
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• pp.127-148
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• 2023

In this study, we used an analysis of the literature on socio-scientific issues (SSI) classes to examine domestic SSI class research and to determine the characteristics of SSI class research for each subject. A search for papers related to SSI classes published in Korea Citation Index-listed journals and candidate journals of the Korea Research Foundation found 95 relevant papers, which were then categorized according to participants and topics. Studies with both pre-service and experienced teachers attempted to investigate SSI-related perceptions. Studies of pre-service teachers tended to examine the level and development pattern of argumentation or to analyze decision-making characteristics and informal reasoning. Studies of experienced teachers tended to analyze instructional expertise in SSI teaching activities, focusing on teachers with substantial SSI teaching experience. Middle and high school students-related studies examined student decision-making and reasoning processes in SSI learning activities, developed SSI class programs, and analyzed educational effects. Examining the characteristics of SSI classes for elementary school students was difficult because few such studies have been published. However, the characteristics that elementary school students show in SSI learning situations could be inferred. A plan to revitalize SSI classes in the elementary science education field from the perspective of teacher education and class research is suggested.

• Journal of Science Education
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• v.42 no.1
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• pp.12-26
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• 2018

This study examined the effects of SSI argumentation program on the preservice biology teachers' decision-making types and communication ability. The SSI argumentation program was developed based on 'Social Decision-Making & Problem-Solving strategy' and Toulmin's argumentation pattern. The preservice teachers had opportunities of SSI argumentation through small group discussions. They were asked to identify the issues regarding SSI, think of solutions, and make a decision along with claims, warrants, data, and rebuttals. The preservice biology teachers experienced four SSI topics of abortion, euthanasia, gene manipulation, artificial intelligence. The results indicated that the preservice biology teachers significantly improved the communication ability after the intervention, but they did not change their types of decision-making. In addition, after the intervention, the Pearson correlation results indicated that 'the logical type' of decision-making significantly relates to the communication ability(p<.01). The preservice biology teachers mentioned that they improved their ability of considering warrants, data, background information, context, and rebuttals. Further, the preserivce biology teachers mentioned that they became take an interest in socioscientific issues and improved their ability of accepting criticism from others as well as caring about others when they argue each other. This study implicated that the SSI argumentation program has effects on improving personality education in school science.

• Earthquakes and Structures
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• v.16 no.1
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• pp.11-28
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• 2019

This article investigates the response of Integral Abutment Bridges (IAB) when subjected to a sequence of seasonal thermal loading of the deck followed by ground seismic shaking in the longitudinal direction. Particular emphasis is placed on the effect of pre-seismic thermal Soil-Structure Interaction (SSI) on the seismic performance of the IAB, as well as on the ability of various backfills configurations, to minimize the unfavorable SSI effects. A series of two-dimensional numerical analyses were performed for this purpose, on a complete backfill-integral bridge-foundation soil system, subjected to seasonal cyclic thermal loading of the deck, followed by ground seismic shaking, employing ABAQUS. Various backfill configurations were investigated, including conventional dense cohesionless backfills, mechanically stabilized backfills and backfills isolated by means of compressive inclusions. The responses of the investigated configurations, in terms of backfill deformations and earth pressures, and bridge resultants and displacements, were compared with each other, as well as with relevant predictions from analyses, where the pre-seismic thermal SSI effects were neglected. The effects of pre-seismic thermal SSI on the seismic response of the coupled IAB-soil system were more evident in cases of conventional backfills, while they were almost negligible in case of IAB with mechanically stabilized backfills and isolated abutments. Along these lines, reasonable assumptions should be made in the seismic analysis of IAB with conventional sand backfills, to account for pre-seismic thermal SSI effects. On the contrary, the analysis of the SSI effects, caused by thermal and seismic loading, can be disaggregated in cases of IAB with isolated backfills.

• Structural Engineering and Mechanics
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• v.28 no.1
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• pp.89-105
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• 2008

The paper presents a study on the effects of soil-structure-interaction (SSI) on the performance of the compliant liquid column damper (CLCD) for the seismic vibration control of short period structures. The frequency-domain formulation for the input-output relation of a flexible-base structure with CLCD has been derived. The superstructure has been modeled as a linear, single degreeof-freedom (SDOF) system. The foundation has been considered to be attached to the underlying soil medium through linear springs and viscous dashpots, the properties of which have been represented by complex valued impedance functions. By using a standard equivalent linearization technique, the nonlinear orifice damping of the CLCD has been replaced by equivalent linear viscous damping. A numerical stochastic study has been carried out to study the functioning of the CLCD for varying degrees of SSI. Comparison of the damper performance when it is tuned to the fixed-base structural frequency and when tuned to the flexible-base structural frequency has been made. The effects of SSI on the optimal value of the orifice damping coefficient of the damper has also been studied. A more convenient approach for designing the damper while considering SSI, by using an established model of a replacement oscillator for the structure-soil system has also been presented. Finally, a simulation study, using a recorded accelerogram, has been carried out on the CLCD performance for the flexible-base structure.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 1999.10a
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• pp.137-146
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• 1999

The SSI(Soil-Structure Interaction) analyses are being performed for the KNGR(Korean Next Generation Reactor) design because the KNGR is developed as a standard nuclear power plant concept enveloping various soil conditions. the SASSI program which adopts the flexible volume method is used for the SSI analyses. The soil curves used in the three dimensional SSI analyses of KNGR Nuclear Island(NI) structures are based on the upper bound shear modulus curve and lower bound damping degradation on SSI response the average shear modulus curve with average damping curve was used for two soil cases. This study presents the results of the variances by using different soil nonlinearity parameters based on the paametric SSI analyses. The results include the maximum member forces(shear and axial force) at the base of the NI structures and the 5% damping Floor Response Spectra (FRS) at some representative locations at the top of the NI superstructures. They are also compared together with the enveloped SSI results for eight soil cases and fixed-base analysis for rock case by using two control motions.

• Structural Engineering and Mechanics
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• v.63 no.1
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• pp.115-124
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• 2017

In this paper, a different technique to predict the effects of soil-structure interaction (SSI) on seismic response of building systems is investigated. The technique use a machine learning algorithm called Support Vector Regression (SVR) with technical and analytical results as input features. Normally, the effects of SSI on seismic response of existing building systems can be identified by different types of large data sets. Therefore, predicting and estimating the seismic response of building is a difficult task. It is possible to approximate a real valued function of the seismic response and make accurate investing choices regarding the design of building system and reduce the risk involved, by giving the right experimental and/or numerical data to a machine learning regression, such as SVR. The seismic response of both single-degree-of-freedom system and six-storey RC frame which can be represent of a broad range of existing structures, is estimated using proposed SVR model, while allowing flexibility of the soil-foundation system and SSI effects. The seismic response of both single-degree-of-freedom system and six-storey RC frame which can be represent of a broad range of existing structures, is estimated using proposed SVR model, while allowing flexibility of the soil-foundation system and SSI effects. The results show that the performance of the technique can be predicted by reducing the number of real data input features. Further, performance enhancement was achieved by optimizing the RBF kernel and SVR parameters through grid search.