• Steel and Composite Structures
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• 제45권5호
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• pp.715-728
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• 2022

Closed steel supports of different shapes are used in mining and underground constructions. The supports are prefabricated from rolled, usually robust, steel profiles. The load carrying capacity of a support is considerably influenced by the active loading and passive forces. The passive forces are induced by interactions between the support and the surrounding rock mass. The analysis herein comprises three parts: The first part consists of structural geometry processing. The second part involves finding the numerical solution of a statically indeterminate structure for a specified load. The third part is calculation of the load carrying capacity and the components of internal forces and deformations. For this, the force method and numerical integration are used. The Winkler model is applied when the support interacts with the surrounding environment. The load carrying capacity is limited by the slip resistance of the connected parts and it is limited by reaching the ultimate state of the profile. This paper serves as a comprehensive reference for the determination of the load carrying capacity of closed steel supports and includes stepwise derivations of the governing formulas.

• Structural Engineering and Mechanics
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• 제88권1호
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• pp.95-107
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• 2023

In this study, circular thin-walled reinforced high strength concrete-filled steel tube (RHSCFST) stub columns with various tube thicknesses (i.e., 1.8, 2.5 and 3.0mm) and reinforcement ratios (i.e., 0, 1.6%, 2.4% and 3.2%) were fabricated to explore the influence of these factors on the axial compressive behavior of RHSCFST. The obtained test results show that the failure mode of RHSCFST transforms from outward buckling and tearing failure to drum failure with the increasing tube thickness. With the tube thickness and reinforcement ratio increased, the ultimate load-carrying capacity, compressive stiffness and ductility of columns increased, while the lateral strain in the stirrup decreased. Comparisons were also made between test results and the existing codes such as AIJ (2008), BS5400 (2005), ACI (2019) and EC4 (2010). It has been found that the existing codes provide conservative predictions for the ultimate load-carrying capacity of RHSCFST. Therefore, an accurate model for the prediction of the ultimate load-carrying capacity of circular thin-walled RHSCFST considering the steel reinforcement is developed, based on the obtained experimental results. It has been found that the model proposed in this study provides more accurate predictions of the ultimate load-carrying capacity than that from existing design codes.

• 환경정책연구
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• 제13권4호
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• pp.107-133
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• 2014

생태관광은 이용과 보전 사이에서 다양한 문제점을 낳고 있다. 이를 극복하기 위해 대상지에 대한 수용력 파악과 적절한 탐방객 수 조절 등의 과학적인 관리기법의 도입이 필요한 상황이다. Getz, LAC, VIM, VERP 관리모델은 이와 같은 목적을 위해 개발되었으며, 국내에서도 도입 및 적용하기 위해 연구되었던 수용력 기반의 관리모델이다. 그러나 우리나라의 생태관광 특성 및 현황, 목적에 적합한 관리모델로의 수정 보완이 필요한 실정이다. 이에 따라 기존의 관리모델을 비교 검토하여 문제점을 파악하였으며, 크게 3가지 개선항목을 제시하였다. 첫째는 수용력과 관리목표의 상호의존적 연계 시스템 개선이며, 둘째는 관광기회분포모형의 개선이다. 셋째는 단계적 관리체계의 개선이다. 이를 통해 최소의 노력과 비용으로 생태관광지역의 탐방객 영향을 효과적으로 관리하는 데 도움을 줄 수 있을 것으로 기대된다.

• International Journal of Naval Architecture and Ocean Engineering
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• 제9권6호
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• pp.705-719
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• 2017

Progressive Collapse Method (PCM) has been broadly applied to predict moment-carrying capacity of a hull girder, however accuracy of PCM has not been much studied. Accuracy of PCM is known to be dependent on how Load-Shortening and -Elongation (LSE) curve of a structural units are well predicted. This paper presents a new procedure to determine LSE datum based on box girder Finite Element Analyses (FEAs) instead of using finite element model of stiffened panels. To verify reliability of FEA results, the simple box girder collapse test results are compared with FEA results of same box girders. It reveals one frame-based box girder model is sufficiently accurate in terms of ultimate strengths of the box girders. After extracting LSE data from the box girders, PCM-based moment-carrying capacities are compared with those from FEAs of the box girders. PCM results are found to be equivalent to FEAs in terms of moment-carrying capacity if accurate LSE data are secured. The new procedure is applied to well-known 1/3 scaled frigate full section. Very excellent moment-carrying capacity of frigate hull section is obtained from PCM with LSE data from box girder FEAs.

• 한국수산과학회지
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• 제29권5호
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• pp.709-715
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• 1996

가막만의 굴양식장 환경용량을 산정하기 위해 생태계 모델을 이용하여 월별 기초생산력을 산정하고 년간 식물플랑크톤의 생산량을 구하여 얼굴로서의 전환계수를 사용하여 굴의 최대 생산 가능량 즉 환경용량을 산정 하였다. 1994년 6월부터 1995년 3월까지 굴양식기간 동안의 가막만 전체에서의 식물플랑크톤 생산량은 181,594 tonC이였고 최대 알굴 생산가능량은 287,033 ton이었고 단위용적당 생산가능량은 $0.29kg/m^3/year$였다. 가막만내에서 굴양식시설이 되어 있는 공간에서의 년간 최대 알굴생산 가능량은 15,443 ton이고 1994년도 실제 알굴생산량은 4,532 ton이므로 굴양식장 환경용량의 약 $29\%$에 해당되었고 1987년도 생산량은 14,592 ton이므로 환경용량의 $95\%$에 해당되었다. 따라서 다른 굴양식장 관리조건만 허용된다면 가막만에는 굴양식시설대수를 증가시키면 생산량이 더 증가할 수 있는 해역으로 평가되었다.

• Structural Monitoring and Maintenance
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• 제9권1호
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• pp.81-105
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• 2022

The use of concrete filled steel tube (CFST) column is widely accepted due to its property of high axial load carrying capacity, more ductility and more resistant to earthquake specially using in bridges and high-rise buildings. The initial imperfection (δ) that produces during casting or fixing causes the reduction in load carrying capacity, this is the reason, experimental capacity is always less then theoretical one. In this research, the effect of δ on load carrying capacity and behavior of concrete filled steel tube (CFST) column have been investigated by numerically simulation of large number of models with different δ and other geometric parameters that include length (L), width (B), steel tube thickness (t), f'_c and f_y. Finite element analysis software ANSYS v18 is used to develop model of SCFST column to evaluate strength capacity, buckling and failure pattern of member which is applied during experimental study under cyclic axial loading. After validation of results, 42 models with different parameters are evaluated to develop empirical equation predicting axial load carrying capacity for different value of δ. Results indicate that empirical equation shows the 0 to 9% error for finite element analysis Forty-two models in comparison with ANSYS results, respectively. Empirical equation can be used for predicting the axial capacity of early estimating the axial capacity of SCFT column including 𝛿.

• Structural Engineering and Mechanics
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• 제48권1호
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• pp.57-75
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• 2013

It is still inadequate for investigating the highly nonlinear and complex mechanical behaviors of single-layer latticed domes by only performing a force-based demand-capacity analysis. The energy-based balance method has been largely accepted for assessing the seismic performance of a structure in recent years. The various factors, such as span-to-rise ratio, joint rigidity and damping model, have a remarkable effect on the load-carrying capacity of a single-layer latticed dome. Therefore, it is necessary to determine the maximum load-carrying capacity of a dome under extreme loading conditions. In this paper, a mechanical model for members of the semi-rigidly jointed single-layer latticed domes, which combines fiber section model with semi-rigid connections, is proposed. The static load-carrying capacity and seismic performance on the single-layer latticed domes are evaluated by means of the mechanical model. In these analyses, different geometric parameters, joint rigidities and roof loads are discussed. The buckling behaviors of members and damage distribution of the structure are presented in detail. The sensitivity of dynamic demand parameters of the structures subjected to strong earthquakes to the damping is analyzed. The results are helpful to have a better understanding of the seismic performance of the single-layer latticed domes.

• 한국산림과학회지
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• 제98권3호
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• pp.297-304
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• 2009

본 연구는 국립공원 입장료 폐지 후 탐방수요가 급증한 북한산국립공원의 사회 심리적 수용력을 평가하고 생태적 수용력 관리를 위한 단계별 관리전략 마련을 위해 수행되었다. 현지 설문조사는 2008년 10월 북한산국립공원 탐방객 512명을 대상으로 이루어졌다. 한계효용이론 모델을 이용하여 분석한 결과 북한산국립공원의 1일 사회 심리적 수용력은 약 65,000명으로 추정되었다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2007년도 추계학술대회 논문집
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• pp.1077-1092
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• 2007

The structural analysis model for estimate of load carrying capacity of railway bridge on service line is important to determine safety of bridges in service, we need to take response of bridge exactly, applying analysis model similar to the real railway bridge most. Track structure which is to distribute loads and decrease vibrations occurred from running train is constructed on the railway bridges. And it is important factor which should be considered to understand exact dynamic and static responses of bridge. But track structure is currently classified as a none structural members in the structural analysis model for estimating load carrying capacity of railway bridge and not considered in analysis model. That's the reason it is difficult to understand exact behavior of bridges. Therefore, the major objective of this study is to develop an analytical track-bridge model which is similar to real railway bridges considering track structure for safety assessment of railway bridge on service line to be effectively done.

• 환경영향평가
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• 제18권1호
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• pp.1-9
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• 2009

Even though the center of Cheongju city needs redevelopment because of a doughnut phenomenon, it has to be permitted within the environmental carrying capacity like a target water quality proposed on the Total maximum daily loads(TMDL) of Musim and Miho river watersheds. The aim of in this study is to identify the limit of redeveloping Cheongju downtown after analyzing its environmental carrying capacity using QUAL2E model. As a result of modeling various scenarios, the water quality of Musin river was shown that $BOD_5$ is 2.3mg/L which is the target water quality in the double of existing development plan of the Cheongju downtown. The water quality of Miho river was $BOD_5$ 3.97mg/L which is less than the target water quality of Miho B watershed in the same condition. Therefore, this means that the limit of redevelopment within the environmental carrying capacity of cheongju downtown was estimated to be the double of existing development plan.