• 한국공간구조학회논문집
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• 제18권1호
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• pp.109-116
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• 2018

As the number of high-rise buildings increases, a mid-story isolation system has been proposed for high-rise buildings. Due to structural problems, an appropriate isolation layer displacement is required for an isolation system. In this study, the mid-story isolation system was designed and the seismic response of the structure was investigated by varying the yield strength and the horizontal stiffness of the seismic isolation system. To do this, a model with an isolation layer at the bottom of $15^{th}$ floor of a 20-story building was used as an example structure. Kobe(1995) and Nihonkai-Chubu(1983) earthquake are used as earthquake excitations. The yield strength and the horizontal stiffness of the seismic isolation system were varied to determine the seismic displacement and the story drift ratio of the structure. Based on the analytical results, as the yield strength and horizontal stiffness increase, the displacement of the isolation layer decreases. The story drift ratio decreases and then increases. The displacement of the isolation layer and the story drift ratio are inversely proportional. Increasing the displacement of the isolation layer to reduce the story drift ratio can cause the structure to become unstable. Therefore, an engineer should choose the appropriate yield strength and horizontal stiffness in consideration of the safety and efficiency of the structure when a mid-story isolation system for a high-rise building is designed.

• 지질공학
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• 제18권4호
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• pp.493-499
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• 2008

본 연구에서는 수평하중을 받는 화강편마암에 근입된 대구경현장타설말뚝에 대하여 수평방향의 거동특성을 분석하기 위하여 시험말뚝인 단일대구경현장타설말뚝 내부에 경사계를 설치하여 단계별 수평하중이 대한 심도별 변위량을 측정하였다. 실측치와 기존 이론식에 의한 계산치를 비교 분석하여 수평변위 거동특성을 평가하였다. 따라서, 단계별 재하하중에 따른 수평변위량의 계측값과 비교한 결과 전체적으로 Chang의 산정식과 유사한 결과를 나타내고 있으나 약간 과소평가 되는 경향이 있다. 그리나 유한차분법(FDM)과 p-y곡선법은 상부구간에서 과대평가 되는 경향을 나타내었다.

• Earthquakes and Structures
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• 제24권3호
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• pp.205-215
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• 2023

Currently, many studies are underway at home and abroad on the seismic performance evaluation and dry construction method of the masonry structure. In this study, a dry stack masonry wall system without mortar using concrete blocks is proposed, and investigate the seismic performance of dry filling wall frames through experimental studies. First, two types of standard blocks and key blocks were designed to assemble dry walls of concrete blocks. And then, three types of experiments were manufactured, including pure frame, 1/2 height filling wall frame, and full height filling wall frame, and cyclic load experiments in horizontal direction were performed to analyze crack patterns, load displacement history, rebar deformation yield, effective stiffness change, displacement ductility, and energy dissipation capacity. According to the experimental results, the full height filling wall frame had the largest horizontal resistance against the earthquake load and showed a high energy dissipation capacity. However, the 1/2 height filling wall frame requires attention because the filling wall constrains the effective span of the column, limiting the horizontal displacement of the frame. In addition, the concrete block was firmly assembled in the vertical direction of the wall as the horizontal movement between the concrete blocks was allowed within installation margin, and there was no dropping of the assembled concrete block.

• 한국지반신소재학회논문집
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• 제22권2호
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• pp.55-61
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• 2023

본 연구에서는 제주 지역의 대표적인 지반 특성(클링커층)을 고려한 흙막이벽의 측방토압 적용을 고찰하기 위해 2개의 현장 사례를 이용하여 수평변위에 대한 계측값과 예측값을 비교하였다. 흙막이벽의 수평변위 발생에 기인하는 측방토압 예측은 Rankine 토압, Terzaghi & Peck 수정측방토압, Tschebotarioff 측방토압을 이용하여 탄소성해석을 실시하였다. 그 결과, A현장에서 예측된 최대 수평변위는 계측값에 비하여 약 5배가 큰 것으로 확인되었으며, 예측에 의한 최대 수평변위 발생 지반은 클링커층으로 나타났다. 그리고 B현장의 경우에는 예측값이 계측값에 비하여 4배에서 최대 7배까지 크게 나타났으며, 최대 수평변위가 발생한 지반과 수평변위 발생 경향은 예측 방법에 따라 매우 다른 경향을 보였다. 이는 암반층과 클링커층이 교호되어 분포되는 제주 지역의 다층지반 특성에 기인한 것이라 판단되기 때문에, 지역 특성을 고려할 수 있는 측방토압에 관한 연구가 지속될 필요가 있음을 의미한다.

• 한국산학기술학회논문지
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• 제22권5호
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• pp.143-150
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• 2021

본 연구에서는 지진시 옹벽의 수평변위량을 예측하는 기법을 개발하고자 옹벽과 지반의 진동시스템에 대한 운동 방정식을 유도하고 그로부터 도출되는 미분방정식은 Runge-Kutta-Nystrom 방법을 이용하여 해를 구하였다. 이러한 계산과정을 고려하여 지진시 옹벽의 수평변위를 얻는 해석과정을 프로그램화하였는데 해석기법의 핵심이 되는 변위-힘 관계를 탄성완전소성으로 모델링하는 계산 알고리즘을 제시하였다. 개발된 프로그램을 가정한 옹벽문제에 적용한 결과 해석을 통해 얻은 시간-변위관계와 시간-힘 관계 그리고 변위-힘 관계는 합리적인 결과를 보임을 알 수 있었다. 본 연구를 통해 개발된 해석기법에 의하면 진동시간이 경과함에 따라 옹벽에는 전면방향으로 변위가 발생되게 되는데 사이클당 변위량은 시간이 경과됨에 따라 일정한 값에 수렴됨을 알 수 있었다. 자연 진동주기에 따른 옹벽의 변위를 계산해 보았는데 한 개의 스프링을 적용한 경우의 스프링상수로부터 유도되는 자연 진동주기가 지진 진동주기와 같을 때 보다는 약간의 차이를 보일 때 변위가 가장 크게 계산되었다. 이러한 이유는 옹벽-지반 진동시스템이 강성이 다른 두 개의 스프링으로 모사되었기 때문으로 볼 수 있다.

• 대한치과교정학회지
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• 제44권6호
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• pp.312-319
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• 2014

Objective: Facial-type-associated variations in diagnostic features have several implications in orthodontics. For example, in hyperdivergent craniofacial types, growth imbalances are compensated by displacement of the condyle. When diagnosis and treatment planning involves centric relation (CR), detailed knowledge of the condylar position is desirable. The present study aimed to measure condylar displacement (CD) between CR and maximum intercuspation in three facial types of an asymptomatic orthodontic population. Methods: The study was conducted in 108 patients classified into three groups of 36 individuals each (27 women and 9 men; mean age, 20.5 years), based on the following facial patterns: hyperdivergent, hypodivergent, and intermediate. To quantify CD along the horizontal and vertical axes, the condylar position was analyzed using mounted casts on a semi-adjustable articulator and a mandibular position indicator. The Student t-test was used to compare CD between the groups. Results: Vertical displacement was found to be significantly different between the hyperdivergent and hypodivergent groups (p < 0.0002) and between the hyperdivergent and intermediate groups (p < 0.0006). The differences in horizontal displacement were not significant between the groups. In each group, vertical CD was more evident than horizontal displacement was. Conclusions: All facial types, especially the hyperdivergent type, carried a significantly high risk of CD. Therefore, the possibility of CD should be carefully evaluated and considered in the assessment of all orthodontic cases in order to accurately assess jaw relationships and avoid possible misdiagnosis.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2006년도 춘계 학술발표회 논문집
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• pp.846-853
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• 2006

In this study, quantitative sensitivity analysis on rockfill material influencing the dam crest displacement of Concrete-Faced Rockfill Dam(CFRD) was carried out. The purpose of this study is to indicate the most important input parameter and to show the quantitative variation of displacement at the crest of CFR type dam with this input parameter. The rockfill material properties for parametric study were obtained from the results of large scale triaxial tests on 34 rockfill materials in the 22 different sites. From the statistical analysis on these data, some statistical characteristics of rockfill material properties such as property range, distribution characteristics, and correlation between the properties were investigated. based on these characteristics, 27 property combinations were constituted by Latin Hypercube sampling method. Dam crest displacements after construction, impounding, and earthquake loading were evaluated by static and dynamic numerical analysis on each combination. From the sensitivity analysis, it was found that the crest displacement of CFR type dam was absolutely affected by the shear modulus of rockfill material and the effect of friction angle of it was negligible. This relative difference of sensitivity was more outstanding in case of crest settlement than in case of crest horizontal displacement. Also, it was found that the settlement and horizontal displacement of dam crest logarithmically decreased as the shear modulus increased and the difference between the maximum value and the minimum vale amounted to about 9.5 times in case of settlement and about 10 times in case of horizontal displacement.

• 산업기술연구
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• 제32권A호
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• pp.79-86
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• 2012

In this paper, centrifuge model tests and numerical analysis on the breakwater structure were performed to investigate the stability and behavior of breakwater in field. In centrifuge model tests, construction sequence of breakwater structure such as preparation of weathered rock and sand deposit, construction of D.C.M, rubble mound with crushed stones and installment of breakwater structure was reconstructed like field condition and the behavior of ground settlement and breakwater displacement during stage of construction was observed during tests. For the final stage of simulating the horizontal movement of breakwater due to wave force, horizontal load was applied by horizontal loading apparatus being specially designed so that horizontal displacement of structure could be observed. Numerical analysis were also carried out and its results were compared with test results to assess the property of centrifuge model tests with respect to the behavior of structure as well as ground.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2002년도 가을 학술발표회 논문집
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• pp.398-403
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• 2002

The low slump mortar grouting is widely used in reinforcement of structural foundation and ground improvement in soft ground. It also has merit that construction is possible in insufficient space. In this study, the main purpose is to evaluate effects for contiguous structures that can be happened along with soft ground improvement by the low slump mortar grouting. To estimate these effects, numerical analysis using finite difference method was applied. It was performed to analyze settlement, upheaval and horizontal displacement of surrounding ground and to measure horizontal stress variation by the first and the second grouting in the pile foundation.

• 한국지반공학회논문집
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• 제28권9호
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• pp.5-15
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• 2012

연직배수공법이 적용된 연약지반의 측방유동 특성을 조사하기 위해 우리나라 해안지역에서 계측관리가 실시된 13개 연약지반 현장의 자료를 수집하여 조사 분석을 실시하였다. 먼저 성토규모가 연약지반의 측방유동에 미치는 영향을 분석하였다. 연약층의 두께와 상대적 도로성토규모가 클수록 연약지반 속의 수평변위는 크게 발생하였다. 특히 연약지반이 두꺼우면 도로성토저면폭에 대한 연약층의 두께의 비인 상대적 성토규모도 자연 커지므로 수평변위량은 크게 발생하였다. 또한 도로성토속도가 빠르면 연약지반의 수평변위량이 크게 발생하였다. 그 밖에도 연약지반의 두께와 비배수전단강도, 지반계수 및 안정수는 연약지반의 측방유동에 영향을 미치는 중요한 요소로 나타났다. 즉 연약지반의 비배수전단강도와 지반계수가 작을수록 그리고 안정수가 클수록 연약지반의 최대수평변위량은 크게 발생하였다. 도로성토로 인하여 연약지반 속에 전단변형이 발생되지 않는 안전한 상태에서는 안정수가 3이하가 되고 지지 안전율이 1.7이상이 되었다. 그러나 연약지반 속에 전단파괴가 발생되는 불안전한 상태에서는 안정수가 5.14이상이 되고 지지안전율이 1.0이하가 되었다. 도로성토로 인하여 연약지반 속에 전단변형이 발생하는지 여부를 판단할 수 있는 허용최대수평변위량의 기준은 50mm로 정하는 것이 바람직하며 연약지반에 전단파괴가 발생됨이 없이 도로성토를 실시할 수 있는 연약지반의 수평변위량 기준은 100mm로 정하는 것이 바람직할 것이다.