• 한국지진공학회:학술대회논문집
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• 한국지진공학회 2001년도 추계 학술발표회 논문집 Proceedings of EESK Conference-Fall 2001
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• pp.251-259
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• 2001

본 논문은 직접 변위 설계법의 기본개념을 이용하여 비대칭 평면을 갖는 벽 식구조의 변위에 근거한 내진설계방법을 제안한다. 제안된 설계방법은 구조시스템의 각 벽체의 강도비와 강성비 및 목적 설계 변위를 결정하고, 직접 변위 설계법에 따라 설계하중은 구하는 과정으로 이루어진다. 탄성 영역에서는 강성 편심을, 비탄성 영역에서는 강도 편심을 주요한 설계변수로 사용하였다 성능에 기초한 내진설계의 개념에 따라 비대칭 평면을 갖는 구조물이 요구되는 성능 수준을 효과적으로 만족할 수 있도록 본 논문은 시스템의 비틀림 미케니즘과 각 벽체의 변형능력을 고려하였다. 제안된 설계방법을 이용하여 중진과 강진 지역에 대해 예제 구조물의 설계하중을 구하고, 최적의 설계방법을 제안하였다.

• Structural Engineering and Mechanics
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• 제5권1호
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• pp.51-58
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• 1997

The influence of bi-directional earthquake-induced loading on eccentric (plan-asymmetric) building systems has been investigated. In the first part of the study, comparisons have been made with equivalent results from uni-directional studies. The results are important in developing analytical models appropriate to the formulation of design recommendations. It is concluded that for valid comparisons, both perpendicular horizontal earthquake components must be considered when using models with transversely-orientated elements. In the second part of the study, an assessment has been made of a simplified, unidirectional (lateral) design approach. For stiffness-eccentric systems, the latter approach gives accurate and reasonably conservative estimates of the critical flexible-edge deformation, but may under estimate the stiff-edge element ductility demand by a factor of two in the short-period range.

• Coupled systems mechanics
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• 제6권1호
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• pp.55-74
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• 2017

The evaluation of torsional effects on multistory buildings remains an open issue, despite considerable research efforts and numerous publications. In this study, a large number of multiple test structures are considered with normally distributed topological attributes, in order to quantify the statistically derived relationships between the torsional criteria and response parameters. The linear regression analysis results, depict that the center of twist and the ratio of torsion (ROT) index proved numerically to be the most reliable criteria for the prediction of the modal rotation and displacements, however the residuals distribution and R-squared derived for the ductility demands prediction, was not constant and low respectively. Thus, the assessment of the torsional parameters' contribution to the nonlinear structural response was investigated using artificial neural networks. Utilizing the connection weights approach, the Center of Strength, Torsional Stiffness and the Base Shear Torque curves were found to exhibit the highest impact numerically, while all the other torsional indices' contribution was investigated and quantified.

• Earthquakes and Structures
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• 제7권4호
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• pp.587-607
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• 2014

Progressive collapse, which is referred to as the collapse of the entire building under local damages, is a common failure mode happened by earthquakes. The collapse process highly depends on the whole structural system. Since, asymmetry of the building plan leads to the local damage concentration; it may intensify the progressive collapse mechanism of asymmetric buildings. In this research the progressive collapse of regular and irregular 6-story RC ordinary moment resisting frame buildings are studied in the presence of the earthquake loads. Collapse process and collapse propagation are investigated using nonlinear time history analyses (NLTHA) in buildings with 5%, 15% and 25% mass asymmetry with respect to the number of collapsed hinges and story drifts criteria. Results show that increasing the value of mass eccentricity makes the asymmetric buildings become unstable earlier and in the early stages with lower number of the collapsed hinges. So, with increasing the mass eccentricity in building, instability and collapse of the entire building occurs earlier, with lower potential of the progressive collapse. It is also demonstrated that with increasing the mass asymmetry the decreasing trend of the number of collapsed beam and column hinges is approximately similar to the decreasing trend in the average story drifts of the mass centers and stiff edges. So, as an alternative to a much difficult-to-calculate local response parameter of the number of collapsed hinges, the story drift, as a global response parameter, measures the potential of progressive collapse more easily.

• Earthquakes and Structures
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• 제10권5호
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• pp.1049-1066
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• 2016

An approximate analysis is presented for multi-story setback buildings subjected to ground motions. Setback buildings with mass and stiffness discontinuities are common in modern architecture and quite often they are asymmetric in plan. The proposed analysis provides basic dynamic data (frequencies and peak values of base resultant forces) and furthermore an overview of the building response during a ground excitation. The method is based on the concept of the equivalent single story system, which has been introduced by the author in earlier papers for assessing the response of uniform in height buildings. As basic quantities of the dynamic response of elastic setback buildings can be derived by analyzing simple systems, a structural layout of minimum elastic rotational response can be easily constructed. The behavior of such structural configurations, which is basically translational into the elastic phase, is also examined into the post elastic phase when the strength assignment of the various bents is based on a planar static analysis under a set of lateral forces simulating an equivalent 'seismic loading'. It is demonstrated that the almost concurrent yielding of all resisting elements preserves the translational response, attained at the end of the elastic phase, to the post elastic one.

• 한국수자원학회논문집
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• 제50권9호
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• pp.647-652
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• 2017

우리나라 해안지역에는 많은 섬들이 위치하고 있어 대규모 지진해일이 발생하였을 때 섬과 지진해일의 상호작용으로 예기치 않은 지진해일 피해가 우려된다. 2011년 발생한 동일본 지진해일의 경우 제주도를 비롯한 남해안 섬들에 영향을 미쳤다. 본 연구에서는 천수이론에 근거한 수치모형을 이용하여 섬 중앙에 대하여 비대칭으로 입사하는 고립파의 처오름높이에 관하여 연구한다. 연구에서 얻은 결과는 지진해일의 급습에 대비한 방재대책을 수립하는데 사용될 수 있을 것이다.

• Earthquakes and Structures
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• 제9권5호
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• pp.1091-1114
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• 2015

The adequacy of a number of advanced earthquake Intensity Measures (IMs) to predict the structural damage of earthquake resistant 3D R/C buildings is investigated in the present paper. To achieve this purpose three symmetric in plan and three asymmetric 5-storey R/C buildings are analyzed by nonlinear time history analysis using 74 bidirectional earthquake records. The two horizontal accelerograms of each ground motion are applied along the structural axes of the buildings and the structural damage is expressed in terms of the maximum and average interstorey drift as well as the overall structural damage index. For each individual pair of accelerograms the values of the aforementioned seismic damage measures are determined. Then, they are correlated with several strong motion scalar IMs that take into account both earthquake and structural characteristics. The research identified certain IMs which exhibit strong correlation with the seismic damage measures of the studied buildings. However, the degree of correlation between IMs and the seismic damage depends on the damage measure adopted. Furthermore, it is confirmed that the widely used spectral acceleration at the fundamental period of the structure is a relatively good IM for medium rise R/C buildings that possess small structural eccentricity.

• 한국주거학회논문집
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• 제25권6호
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• pp.57-66
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• 2014

With regard to the pavilion buildings of Imcheonggak Gunjajeong and Donglakdang Gyejeong that are located within residential areas, this study focused on the construction background, the building owner's circumstances and the location environment of these buildings, and attempted to derive the architectural characteristics presented by these two pavilion buildings and, through this, to grasp the architect's intention of plan. The results of this study are as follows. With regard to Gunjajeong, it could be confirmed that, first, it is located in a propitious site and took the composition that follows the family ritual standards for the family rituals of the scholar-gentry class and opens to visitor access, and second, the floor height of the site and interior space was designed so that Munpilbong on the south and the Sarangchae on the west, and the Sadang on the east can be connected visually, and third, the authority and dignity of the head family were built through the symmetric 丁-shaped plane figure, the wide partition module, the form-centered building, and the hierarchical composition of the roof. On the other hand, with regard to Gyejeong, it could be confirmed that, first, it is located along the stream of Jagye valley that has no mountains in the front and in the back and took the composition that put the name symbolizing Taoist thoughts on the surrounding natural environment and was closed to visitor access but opens to nature, and second, with Jagye and Jagye surroundings as the main landscape, it built the concept of intended landscape that symbolizes the Taoist thoughts by giving names not only simply to the visible objects but also to surrounding rocks, and third, the asymmetric ㄱ-shaped plane composed a yard-centered space rather than emphasizing the shape, and connected the part of the plane with Jagye so as to be embodied as a personal inner self-perfecting place that closely communicates only with nature away from the mundane world.

• Earthquakes and Structures
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• 제12권1호
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• pp.1-12
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• 2017

Historical earthquakes have shown that successive seismic events may occur in regions of high seismicity. Such a sequence of earthquakes has the potential to increase the damage level of the structures, since any rehabilitation between the successive ground motions is practically impossible due to lack of time. Few studies about this issue can be found in literature, most of which focused their attention on the seismic response of SDOF systems or planar frame structures. The aim of the present study is to examine the impact of seismic sequences on the damage level of 3D multistorey R/C buildings with various structural systems. For the purposes of the above investigation a comprehensive assessment is conducted using three double-symmetric and three asymmetric in plan medium-rise R/C buildings, which are designed on the basis of the current seismic codes. The buildings are analyzed by nonlinear time response analysis using 80 bidirectional seismic sequences. In order to account for the variable orientation of the seismic motion, the two horizontal accelerograms of each earthquake record are applied along horizontal orthogonal axes forming 12 different angles with the structural axes. The assessment of the results revealed that successive ground motions can lead to significant increase of the structural damage compared to the damage caused by the corresponding single seismic events. Furthermore, the incident angle can radically alter the successive earthquake phenomenon depending on the special characteristics of the structure, the number of the sequential earthquakes, as well as the distance of the record from the fault.

• 한국지진공학회논문집
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• 제12권4호
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• pp.35-44
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• 2008

최근 새로운 지진하중 저항시스템으로 셀프센터링(SCED) 가새 시스템이 개발되었다. 진보된 가새 시스템인 비좌굴 가새(BRB) 시스템과는 달리 큰 지진이 발생한 후 구조물의 잔류 변형을 줄이거나 없앨 수 있는 셀프센터링 능력은 SCED 가새 시스템의 장점이다. 본 논문에서는 SCED 가새와 BRB 가새 시스템의 거동에 비틀림의 영향을 조사하기 위하여 세 가지 다른 편심을 가진 3차원 구조물의 응답을 비선형 동적해석을 수행하여 비교하였다. 해석결과에 따르면 층간변위의 높이방향의 변화는 비정형성에 관계없이 SCED 가새골조의 응답이 BRB 가새골조보다 일정하였으며, 잔류 층간변위와 잔류 회전 응답은 비정형성이 증가함에 따라 감소하였다. 중층 구조물에서 SCED 가새골조의 변형집중계수(DCF)는 BRB 가새골조보다 작은 것으로 나타났다. 이것은 SCED 가새골조가 건물 높이에 따라 보다 일정하게 변형함을 의미한다. DCF의 크기에 대한 비틀림 비정형의 효과는 작았다.