• Computational Structural Engineering
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• v.10 no.2
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• pp.27-33
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• 1997

현재 일본의 합성구조물의 설계에 관한 기준서는 토목학회 '강구조물의 극한강도와 설계'와 철도종합기술연구소의 '철도구조물등설계표준.동해설(강.합성구조물)'이 있다. 그리고, 토목학회.강구조위원회.강구조 극한강도 연구 소위원회에서 합성구조물의 극한강도 분과회를 조직해서, 한계상태설계법의 포멧에 따라 합성구조물의 설계지침서를 금년 여름경에 출판 할 예정이다. 본인도 합성구조물의 극한강도 분과회의 위원으로 약 3년간동안 많은 공부와 연구를 행할 수 있는 기회를 받았다. 합성구조물의 설계지침서는 합성바닥판, 합성거더와 합성기둥으로 나누어져있으며, 이번에 소개한 부분은 그중 일부분인 합성바닥판의 강판과 철근콘크리트를 적당한 전단연결재로 결합한 합성바닥판의 설계부분이다.

• Journal of the Korea institute for structural maintenance and inspection
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• v.23 no.3
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• pp.96-102
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• 2019

The study of thermal effect on the structure is carried out in the case of Guss asphalt which is paved at the temperature of $240^{\circ}C$ or higher in the bridge pavement of the steel deck bridges. However, studies on the heat source data applicable to numerical analysis are insufficient, the temperature load is used as a joint load. In this study, the heat source equations that can be directly loaded on the plate elements, although limited, are presented using the measured temperature data in the Guss asphalt pavement and its validity is confirmed by a brief numerical analysis.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.12 no.2
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• pp.35-42
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• 1992

The effectiveness of the support-isolation system for the equipment mounted on the primary structure is evaluated to reduce its responses under the earthquake load with considering the interaction between the primary structure and the internal equipment in this paper. A computer code (KBISAP) is developed to analyze the above system using the matrix condensation technique and constant average acceleration method. To evaluate the effectiveness of the support-isolation system, three systems are used in this study as follows: i) fixed-base structure with support-fixed equipment, ii) base-isolated structure with support-fixed equipment and iii) fixed-base structure with support-isolated equipment. The results of case study show that the acceleration of equipment with the support-isolation system is less than that of the support-fixed equipment in the base-isolated structure and significantly reduced the response compared with that of the support-fixed equipment in the fixed-base structure with the reduction factor of 8. The support-isolation system used in this study can reduce the response and also increase the safety margin of the important safety-related internal equipments.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2020.11a
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• pp.50-51
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• 2020

Recently, various maintenance materials and construction methods have been developed to secure the sustainable performance of structures. However, waterproofing of underground structures where groundwater infiltration is present is very difficult. In particular, the location of underground structures such as subways is very deep, and it is difficult to apply waterproof materials and construction methods in the case of structures accompanied by vibration. Therefore, we intend to study materials and methods for waterproofing leakage resistance in special environments such as underground structures.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.32 no.2A
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• pp.117-122
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• 2012

Coastal structures, constructed for preventing coastal slope erosion, often causes the scour on the boundary between the coastal structure and the sea-bed, which might lead to collapse of coastal structures. To prevent the collapse, the usual upright block type coastal structures can be modified to other forms or systems of coastal structures. To validate the performance of the proposed systems, it is necessary to conduct high cost hydraulic experiments. If numerical modeling can be performed prior to the hydraulic experiments and the performance of the proposed systems is analyzed numerically in advance, the expenses can be reduced significantly by optimizing the number of cases for conducting the experiments. In this study, a fluid-structure interaction analysis procedure is proposed for modeling the hydraulic experiments of costal structures using the finite element package, LS-DYNA. As can be found in the usual hydraulic experiments, fluid velocities of potential scour locations are monitored and analyzed in detail for four types of coastal structures, block, step, trapezoid and rubble mound.

• Computational Structural Engineering
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• v.6 no.1
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• pp.107-115
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• 1993

This study is directed for the development of a computer aided safety assessment system for agricultural irrigation structures. The developed system is composed of four subsystems that incorporate database, structural analysis, safety assessment, and postprocess, which are made to be interfaced systematically. It is developed in the user-friendly menu driving form with pull-down type interaction on a personal computer. The main algorithm for safety assessment of deteriorated structures utilizes a rational rating system based on the reliability method. From this study, it may be stated that the proposed rating and safety assessment system provide an effective tool and thus it can be widely used in practice for the assessment of safety and load carrying capacity of existing deteriorated or damaged agricultural irrigation structures.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.2A
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• pp.59-69
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• 2011

Nonlinear static procedures (NSPs) basing on the concept of performance based seismic design have become one of the promising procedures for seismic evaluation of buildings. Although it needs much less computational cost compared to nonlinear time history analysis (NTHA), its usages are limited to simple structures by its inherent restriction to structures wherein the fundamental mode dominates the response. Several new nonlinear static procedures (Modal Pushover Analysis; MPA and Improved Modal Pushover Analysis; IMPA) which can consider higher modes effect were introduced. Nonetheless, its applicability for complex structures such as cable-stayed bridge has not studied yet. This paper focuses on applicability of nonlinear static procedures for the seismic analysis of cable-stayed bridges. Moreover, reliability indexes which can predict analysis procedure's accuracy are introduced.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.1029-1032
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• 2008

Nowadays, the necessity of the NDT technique for concrete structure has been increased due to maintenance of infra-structure. With this reason, NDT detecting technique has been considered as a effective maintenance method to prevent the rapid degradation of the infra-structure. In this study, to investigate the internal defect of concrete structure, ultrasonic detection device and radar equipment was applied then tested in laboratory and field. In the result of the experimental test, the internal cavity and steel arrangement can be detected and it was possible to adopt the ultrasonic detection method to the maintenance of concrete structure. And an algorithm for performing the maintenance procedure of concrete structure applying ultrasonic detection device and radar equipment was developed and suggested in this study.

• Proceedings of the Korea Water Resources Association Conference
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• 2015.05a
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• pp.150-150
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• 2015

최근 하천의 수위조절 기능을 수행하는 보 건설이 증대되고 있다. 보는 원활한 용수공급을 위해 필수적인 구조물이지만, 하천 횡단 구조물의 특성상 유사퇴적에 의한 통수단면적 감소, 홍수위험도 증가, 수질악화 등의 문제를 내포하고 있다. 이를 해결하기 위해 유사시 유사배출이 가능하고 수문개도를 통한 통수단면적 조절로 홍수위험도를 감소시킬 수 있는 가동보를 고정보와 병용해서 적용하는 추세이다. 가동보는 수문 운영 방식에 따라 하류의 흐름상태가 다양하게 나타나며, 흐름 상태에 따라 하도 및 구조물에 미치는 영향도 달라진다. 그러나 기존 가동보 및 보 하류 구조물의 설계 시 일반적으로 수문 운영조건을 고려하지 않고, 홍수위 조건을 최악조건으로 고려하는 한계가 있다. 본 연구에서는 3차원 수치모델(FLOW-3D)을 활용하여 가동보의 운영에 따라 발생하는 다양한 흐름조건이 보 하류에 미치는 영향을 검토하고자 한다. 수치모델의 검증을 위해 기존 수행된 수리실험과의 비교를 수행하였고, 홍수위 조건(수문 전문개도) 및 관리수위 조건(수문 일부개도)에서 수치모의를 수행하였다. 보 상류, 직하류, 도수종점에서 발생하는 단면최대유속, 바닥전단 응력, Froude 수 등의 수리특성을 분석하였고, 상하류간 수심차와 수문개도높이의 비와 접근유속과 보 직하류에서 유출되는 유속의 비로 무차원화하여 관계를 분석하였다. 또한 홍수위 조건과 관리수위 조건에서 발생하는 수리특성을 비교함으로써, 보 하류부 구조물 설계 시 반영할 최악조건을 예측하고, 수문운영이 하류부에 미칠 수 있는 영향을 가시적으로 확인할 수 있었다. 향후 상류의 유량조건 및 상하류 수위차에 따른 가동보의 운영조건이 보 하류의 안정성 지표산정에 활용될 수 있기 위해 보다 심도있는 연구 수행이 필요하다.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.2A
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• pp.119-130
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• 2009

Seismic fragility curves of a structure represent the probability of exceeding the prescribed structural damage state for a given various levels of ground motion intensity such as peak ground acceleration (PGA), spectral acceleration ($S_a$) and spectral displacement ($S_d$). So those are very essential to evaluate the structural seismic performance and seismic risk. The purpose of this paper is to develop seismic fragility curves for PSC box girder bridges. In order to construct numerical fragility curve of bridge structure using nonlinear time history analysis, a set of ground motions corresponding to design spectrum are artificially generated. Assuming a lognormal distribution, the fragility curve is estimated by using the methodology proposed by Shinozuka et al. PGA is simple and generally used parameter in fragility curve as ground motion intensity. However, the PGA has not good relationship with the inelastic structural behavior. So, $S_a$ and $S_d$ with more direct relationship for structural damage are used in fragility analysis as more useful intensity measures instead of PGA. The numerical fragility curves based on nonlinear time history analysis are compared with those obtained from simple method suggested in HAZUS program.