• Journal of Korean Association for Spatial Structures
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• v.10 no.3
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• pp.81-90
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• 2010

Large spatial structures have the different dynamic characteristics from general rahmen structures and many studies on dynamic behavior of it is conducted. But most studies was conducted about the particular shape of large spatial structures and, directly, the usable results of studies are very limited for seismic design of large spatial structures with the lower structure. So, this study is conducted about the truss arch structure that the basic dynamic characteristics of large spatial structure is inherent in, and the change of its seismic response is analyzed when columns have different length on both ends of it. According to the difference of column's length on both ends, the vertical acceleration response of truss arch structure is affected more than the horizontal acceleration response of it. Therefore, when the stiffness of lower structures that support the upper structure is different, the consideration of the vertical response is significantly required for the seismic design of large spatial structures.

• Journal of the Earthquake Engineering Society of Korea
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• v.5 no.5
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• pp.73-83
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• 2001

The mass and stiffness of upper wall-lower frame system(mixed building structures) change sharply at transfer floor due to different structural system in upper and lower part. These mixed building structures generally show the stiffness, weight or geometric vertical irregularities. The purpose of this study is to investigate the response characteristics of these structures by push-over analysis and nonlinear time history analysis. For four types of analysed models, only the variation of upper wall stories was considered. The conclusions of this study are following; (1) In the push-over analysis, yielding hinges in beams and columns of lower frame occurred at the base shear of similar magnitude in all models. But as the number of stories of upper wall increases, yielding hinges at ends of coupling beams were observed in the small magnitude of base shear. (2) In the nonlinear time history analysis, yielding of lower frame occurred at beams with as small ground acceleration as 55gal, and in upper walls yielding was concentrated on coupling beams and shear walls near the transfer floor. (3) As the number of stories of upper walls decreases, the story stiffness of the lower frames decreased relatively and the occurrence of soft stories in the lower frame was observed.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.29 no.1
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• pp.19-28
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• 2016

In the case of structural analysis for building structures, the super-structure and the sub-structure are analyzed by using separate structural models in the field because of time saving, facile result interpretation and easy analysis of dynamic behavior. However this separate structural model violated the compatibility condition of structural analysis and it can not consider the interaction of superand sub- structures. In the present study, the analysis results of this separate model were compared to those of the unified model of super- and sub- structures which can consider the interaction of super- and sub- structures and reflect the realistic boundary conditions. According to the comparison results, the the analysis model using separate models can underestimate the member force and deflection of structural members in the super-structures and overestimate the deflection and member force of sub-structures. Therefore, in the case of high-rise buildings, irregular shaped buildings, buildings which are expected to be affected by large differential settlement and remodeling buildings, the unified structural model for super- and sub- structures was recommended for structural analysis instead of the separate structural model.

• International Journal of Highway Engineering
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• v.11 no.2
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• pp.239-247
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• 2009

Pipe installation following excavation of pavement and underlying-soils induces settlements, cracks and bad roughness near utility cut. This study is to use PMT and LDWT in order to evaluate stiffness and/or degree of compaction of sublayers and backfill in utility cut section because no specially designed efforts for evaluating stiffness condition of the substructures below new pavement after pipe installation are offered at this time. From test results of PMT, comparable stiffness and/or degree of compaction in recompaction process is not obtained comparing to that of the existing sublayers before excavation. Thickness of the new surface layer after pipe installation must be designed thicker than that of the existing surface layer. It is verified that LDWT comparing to PMT is effective only to get stiffness and/or degree of compaction within limited depth from surface of materials, but it is not useful to evaluate stiffness of substructures in full depth in case of utility cut.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.19 no.2 s.72
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• pp.187-194
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• 2006

Generally, earthquake-resistant structural systems have to ensure the sufficient stiffness and ductility for stability In this paper, the spatial structures are applied an isolation system to boundary parts between roof systems and sub-structures. So, it is necessary to examine the characteristics of dynamic behaviors of spatial structures governed by higher modes rather than lower modes different from the cases of high-rise buildings. The objectives of this paper are to develop the equivalent lumped mass model to simplify an analytical processes and to investigate the dynamic behaviors of roof systems according to the mass and stiffness of sub-structures as a fundamental study of performance design for the spatial structures.

• Computational Structural Engineering
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• v.11 no.4
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• pp.331-340
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• 1998

본 연구에서는 이동제한장치가 있는 연속교의 지진응답특성을 고찰하였다. 일점고정연속교에 있어서 이동제한장치는 교각이 탄성거동을 하는 경우 교축방법 수평력 분산기능이 있으며 교각하부에 소성힌지가 발생하거나 내진분리베어링이 있는 경우에는 최대변위 및 비탄성거동에 따른 잔류변위제한에 매우 효과적이다. 상부구조와 이동제한장치의 충돌시 발생하는 충격력은 완충재의 사용으로 상당히 감소시킬 수 있다. 이동제한장치의 설치위치 및 이격거리는 이동제한장치가 설치될 하부구조의 강성 및 강도와 온도변화, 급제동력, 작은 지진발생시 충돌여부, 신축이음장치유간 등을 고려하여 결정되어야 한다.

• Journal of the Earthquake Engineering Society of Korea
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• v.4 no.4
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• pp.1-13
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• 2000

상부벽식 하부골조를 가진 복합구조물은 부족한 대지를 효율적으로 활용하기 위하여 건설되고 있다. 이러한 복합건물은 상부벽식-하부골조를 가지는 구조로써 일반적으로 전이보 또는 전이판으로 상하부를 연결하고 있다. 따라서 상하부 구조사이의 강성과 질량에 많은 차이가 발생하게 된다. 구보물의 고유주기는 지진하중과 밑면전단력을 결정하기 위한 중요한 변수이다. 그러나 현재 국내 규준에서 제안하는 고유주기 산정식은 이러한 건물에는 적용할 수 없다. 본 연구에서는 상부벽식-하부골조를 가진 복합구조물의 고유주기의 산정에 영향을 미치는 변수들 중 가장 큰 영향을 미치는 건물의 상하부 층수에 따른 변수만을 고려하여 고유주기산정식을 제안하였다. 하부는 2~5개 층을 가지고, 상부는 10~18개 층을 가지는 15~20층의 건물이면 정형적인 평면을 가지는 복합구조물로 한정하였다. 건물 내부의 채움벽에 대한 효과를 고려한 고유주기 제안식은 다음과 같다. 장변 방향 : $T_{L}$=($0.20H_{h}+0.05H_{i}$)/$sqrt{B}$-0.42 단변 방향 :$T_{S}$=($0.07H_{h}+0.12H_{i}$)/$sqrt{B}$-0.40

• Journal of the Korean Geotechnical Society
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• v.15 no.2
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• pp.29-42
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• 1999

The SASW (Spectral-Analysis-of-Surface-Waves) method, which evaluates the stiffness structure of the subsurface and structures nonintrusively and nondestructively, has been successfully used in the civil engineering applications. However, the SASW method assumes that the subsurface or structures consist of horizontal multi-layers, so that the method has some difficulty in continuously evaluating the integrity of a tunnel lining and a pavement system. This difficulty prevents the SASW method from being used to generate a tomographic image of stiffness for the subsurface or structures. Recently, the GPR technique which has the advantage of continuously evaluating integrity of the subsurface and structures has been popular. This advantage of GPR technique initiated the efforts to make the SASW method, which is superior to GPR and other nondestructive testing methods due to its capability of evaluating stiffness and modulus, be able to do continuous evaluation of stiffness structure, and the efforts finally lead to the development of \ulcornerTomographic SASW Technique.\ulcorner Tomographic SASW technique is a variation of the SASW method, and can generate a tomographic image of stiffness structure along the measurement line. The tomographic SASW technique was applied to the investigation of lateral variability of a sand box placed by the raining method for the purpose of verifying its effectiveness. Tomographic SASW measurements on the sand box revealed that the investigated sand box has different shear stiffness along the measurement line, which gave a clue of how to make a better raining device.

• Journal of the Earthquake Engineering Society of Korea
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• v.6 no.1
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• pp.55-62
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• 2002

The upper wall-lower frame structures(mixed building structures) are usually composed of shear wall structure in the upper part of structure which is used as residential space and frame structure in the lower part of structure which is used as commercial space centering around the transfer system in the lower part of structure. These structures are characteristics of stiffness irregularity, mass irregularity, and vertical geometric irregularity. The purpose of this study is to investigate the nonlinear response characteristics and the seismic capacity of mixed building structures when the number of stories in the lower frame is varied. The conclusions of this study are following. 1) As the result of push-over analysis of structure such as roof drift(i.e. roof displacement/structural height) and base shear coefficient, when the stories of lower frame system are increased, base shear coefficient is decreased, but roof drift is increased. 2) According to an increase in stories of the lower fame, story drift and ductility ratio of upper wall system are decreased and behavior of upper wall system is closed to elastic. 3) When the stories of lower frame system are increased, the excessive story drift is concentrated on the lower frame system.

• Journal of the Korea institute for structural maintenance and inspection
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• v.15 no.5
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• pp.124-135
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• 2011

The capacity of bearings installed at abutments and piers for continuous bridges is usually determined by the magnitude of the maximum vertical reaction at each support and the capacity of bearings placed at piers is higher than that at abutments. In this study, the possibility of the improved seismic performance of base-isolated continuous skew bridges was investigated by analysing the variation of the seismic behavior of them according to three arrangements of bearings. Based on the conventional arrangement of bearings(Case A), three arrangements of bearings such as Case A, Case B and Case C were selected considering the variation of the horizontal stiffness of the lead rubber bearing(LRB) installed at the pier. The seismic behavior of the total 36 skew bridges was investigated by conducting the response spectrum analysis using the hybrid response spectrum considered the effect of LRB's damping. Results of analyses show that a more desirable seismic behavior of base-isolated continuous skew bridges can be obtained by reducing the magnitude of the horizontal stiffness of LRB placed at the pier to similar to or less than that of LRB installed at abutments. The variation of LRB's stiffness at the pier brings about period elongation and the change of mode shapes of base-isolated skew bridges and results in the reduction of the total base shear, the maximum base shear at the pier and the girder stresses. Although positive effects on the seismic behavior of base-isolated skew bridges caused by the change of arrangement of bearings decreased slighty with an increase in the flexibility of the substructure, the proposed arrangements of bearings bring about the improved seismic performance of base-isolated continuous skew plate girder bridges with less than 10m height of piers.