• Structural Engineering and Mechanics
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• 제51권3호
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• pp.471-485
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• 2014

Until now, the finite corner stiffness of the right-angle frames used as horizontal girders in a bonnet, have not been considered during the design process to result in not a precise result. This paper presents a design equation set for right-angle frames used as horizontal girders in a bonnet assuming rigid corner stiffness. By comparing the center stresses of the right-angle frame according to the design equation set with the results of the finite element method, the master curves for the empirical corner stiffness can be determined as a function of slenderness ratio. A second design equation set for a right-angle frame assuming finite corner stiffness was derived and compared with the first equation set. The master curves for the corner stiffness and the second design equation set can be used to determine the design moments at the centers of the girder so that the bending stresses can be analyzed more precisely.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2003년도 봄 학술발표회 논문집
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• pp.487-495
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• 2003

Bearings at the obtuse corner are subjected to much larger vertical reactions than other bearings because of the geometric shape of skew bridges. The current relevant specifications require that additional bars should be disposed at the bottom of concrete deck slabs to deal with the large vertical reaction on bearings at the obtuse corner. In this study, new methods of reducing the magnitude of the vertical reaction on bearings at the obtuse corner by the stiffness adjustment of bearings were proposed. The basic concept of proposed methods was to redistribute support reactions by reducing the vertical stiffness of bearings at the obtuse corner showing a relatively large vertical reaction. For 45 simply supported skew bridges designed according to the current relevant specifications, the redistribution effect of vertical reactions by the stiffness adjustment of bearings was investigated. Parameters such as skew angle, girder spacing, and deck aspect ratio that affect the distribution of support reactions were considered. The results of the analyses show that the magnitude of the vertical reaction on bearings at the obtuse corner can be reduced to the levels of straight bridges by replacing the existing bearings at the obtuse corner with new ones having the value of 1/10 or 1/20 of the vertical stiffness of the existing bearings. The reduction effect of the vertical reaction on bearings at the obtuse corner increases as the girder spacing decreases and it is more pronounced when the deck aspect ratio is 2.0.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2013년도 춘계학술대회 논문집
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• pp.939-940
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• 2013

• 한국지반신소재학회논문집
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• 제21권2호
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• pp.39-48
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• 2022

사보강버팀보는 수평버팀보와 달리 토압이 발생할 경우 설치각에 의한 휨거동이 발생하기 때문에 버팀보의 축강성만이 요구되는 탄소성해석으로는 그 적용에 대한 한계가 존재한다. 따라서, 본 연구에서는 탄소성해석시의 사보강버팀보에 대한 해석방안을 제시하기 위하여 축강성데이터를 수정하는 방안으로의 접근을 시도하였으며, 이를 위하여 선형탄성해석을 이용하였다. 그리고, 선형탄성해석을 통하여 실제현장에 설치된 사보강버팀보에 대한 축강성데이터를 산정하였다. 산정한 사보강버팀보의 축강성데이터는 탄소성해석에 적용하여 흙막이벽체의 거동을 확인하였으며, 이를 계측결과 및 유한요소해석결과와 비교하여 그 적용성을 평가하였다. 연구 결과 선형탄성해석을 이용하여 사보강버팀보의 축강성데이터를 적용한 경우(Case 1, Case 3)는 버팀보의 축강성을 적용하는 일반적인 방법(Case 2, Case 4)에 비하여 축강성데이터는 9~17% 수준으로 감소하였으며, 탄소성 해석시의 흙막이벽체의 변위는 25.33%~64.42%로 증가하였다. 이 결과를 계측결과와 비교한바 선형탄성해석을 활용한 경우(Case 1, Case 3)는 탄소성해석시의 흙막이벽체 거동을 더욱 잘 나타내었다.

• Steel and Composite Structures
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• 제48권3호
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• pp.321-333
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• 2023

This paper proposes a comprehensive investigation on lateral stiffness of corner-supported steel modular frame using splice connection. A full-scale modular frame with two stacked steel modules under lateral load is tested. Ductile pattern in the transfer of lateral load is found in the final failure mode. Two types of lateral stiffness, including tangent stiffness and secant stiffness, are defined from the load-displacement due to the observed nonlinearity. The difference between these two types of stiffness is found around 20%. The comparisons between the experimental lateral stiffness and the predictions of classical methods are also conducted. The D-value method using hypothesis of independent case is a conservative option for predicting lateral stiffness, which is more recommended than method of contraflexural bending moment. Analyses on two classical short-rod models, including fix-rod model and pin-rod model, are further conducted. Results indicate that fix-rod model is more recommended than pin-rod model to simplify splice connection for simulation on lateral stiffness of modular frame in elastic design stage.

• Earthquakes and Structures
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• 제7권5호
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• pp.891-906
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• 2014

The purpose of this study is to propose a modification factor to reflect the lateral stiffness modification when a step is located in flat plates. Reinforced concrete slabs with steps have different structural characteristics that are demonstrated by a series of structural experiment and nonlinear analyses. The corner at the step is weak and flexible, and the associated rotational stiffness degradation at the corner of the step is identified through analyses of 6 types of models using a nonlinear finite element program. Then a systematic analysis of stiffness changes is performed using a linear finite element procedure along with rotational springs. The lateral stiffness of reinforced concrete flat plates with steps is mainly affected by the step length, location, thickness and height. Therefore, a single modification factor for each of these variables is obtained, while other variables are constrained. When multiple variables are considered, each single modification factor is multiplied by the other. Such a method is verified by a comparative analysis. Finally, a complex modification factor can be applied to the existing effective slab width.

• Journal of the Korean Wood Science and Technology
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• 제17권2호
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• pp.34-64
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• 1989

포장(包裝) 용적(容積) 감소에 따른 수송비(輸送費) 절감(節減) 효과(效果)가 있어 조립시(組立式) 탁자류(卓子類) 가구(家具)의 제작(製作)에 널리 쓰이는 CBA(corner block with anchor bolt) 접합방식(接合方式)은 일정기간(一定期間) 사용(使用)함에 따라 접합부위(接合部位)가 약해지고 그 결과(結果) 구조(構造)가 불안정(不安定)하게 되는 반강접합(半剛接合)(semi-rigid joint) 특유(特有)의 결점(缺點)도 지니고 있다. 따라서 본(本) 연구(硏究)에서는 CBA 접합(接合) 강도(强度)에 영향하는 주요(主要) 설계(設計) 인자(因子)로서 side rail 규격, corner block의 side rail에의 부착시(時) 보강재(補强材)의 효과(效果) 및 corner block관통 anchor bolt의 사용(使用) 수(數) 그리고 corner block의 형태등(等)의 평가(評價)를 하기 위해 22개(個)의 접합군(接合群) 별(別)로 총(總) 88개(個)의 table section 시험체(試驗體)를 제작(製作)한 후(後)그들의 강성(剛性) 계수(係數)(Z - 값) 및 유효강도(有效强度)를 수평 하중(荷重)에 의한 변형측정(變形測定) 실험(實驗)을 통해 결정(決定)한 후 설계(設計) 인자별(因子別) 효과(效果)를 비교 분석(分析)하였다. 분석결과(分析結果), side rail의 높이 증대(增大) 및 corner block 부착시(時) PVAc 수지(樹脂)의 사용효과(使用效果)가 뚜렷하여 유효강도(有效强度)의 유의적(有意的) 향상(向上)을 나타냈고 anchor bolt의 효과(效果) 역시 2개 사용시(使用時)가 1개 사용시(使用時) 보다 훨씬 큰 것으로 나타났다. 또 side rail 높이 와 anchor bolt 사용(使用) 수(數)간에는 상호작용(相互作用) 효과(效果)도 있었다. 그러나 side rail의 두께 효과(效果)는 22mm에서 25mm로 증대(增大)시켰을때 뚜렷한 상승 경향(傾向)은 보여주지 못했다. 한편 corner block의 형태는 MDF를 주재료(主材料)로 사용(使用)한 탁자(卓子) 설계시(設計時)는 두께 25mm, 높이 100mm의 side rail에 PVAc 수지(樹脂)로 보강(補强)하고 mitered corner block에 2개(個)의 anchor bolt를 관통시킨 경우가 유효강도(有效强度) 3171.7 kgf-cm로 22개의 접태군(接台群)들 중 최대치(最大値)를 나타냄으로써 miter type이 rectangular type보다 바람직한 것으로 나타났다. 결론적(結論的)으로 자재(資材)의 효과적(效果的) 이용(利用)을 통한 생산비(生産費) 절감(節減)과 동시(同時)에 구조(構造)의 안정(安定)된 강도적(强度的) 측면(側面)을 고려할 때, 두께 22mm, 높이 75mm의 MDF side rail에 mitered corner block을 PVAc 수지(樹脂)와 나사못을 이용하여 부착한 후(後) 2개(個)의 anchor bolt를 관통시키는 방법(方法)을 가장 합리적(合理的)인 MDF 사용(使用) 조립시(組立式) 탁자(卓子) 설계(設計) 방안(方案)으로 제시(提示)하는 바이다.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2004년도 봄 학술발표회 논문집
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• pp.325-331
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• 2004

Generally, the buckling of thin-walled structures has studied for rectangular sections or circular sections. Rectangular sections have small stiffness and circular sections have large stiffness when they are compared with rectangular sections for local buckling. But both of them have similar stiffness to column buckling. Therefore in this paper, we are going to analyze the local buckling for the box section with rounded comer and compare with rectangular section. Also we confirm that the rounded comer section has larger local buckling strength than rectangular section.

• 한국가스학회지
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• 제13권6호
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• pp.9-14
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• 2009

본 연구에서는 LNG 저장탱크의 단열재 공간에 설치된 코너프로텍션에 작용하는 응력 및 변형거동 특성을 FEM으로 해석하였다. 제시된 코너프로텍션은 기존의 멤브레인식 LNG 저장탱크의 강도안 전성과 LNG 누출안전성을 증대시킬 수 있다. LNG 저장탱크 시스템에 작용하는 응력과 변위 거동량을 단열재 상자, 멤브레인 내부탱크, PC 외부탱크에 대하여 해석하였다. 유한요소법으로 계산한 해석결과에 의하면, 내부탱크와 외부탱크 사이에 코너프로텍션을 설치한 새로운 LNG 멤브레인 저장탱크의 응력과 변형 거동량은 기존의 LNG 저장탱크에 비하여 현저하게 줄어드는 경향을 보여주고 있다. 이러한 현상은 LNG 저장탱크 시스템의 강도 안전성이 코너프로텍션을 설치함에 따라서 강성도가 증가하기 때문인 것으로 설명될 수 있다.

• Computers and Concrete
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• 제27권4호
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• pp.343-353
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• 2021

In this study, in order to improve the seismic performance of existing reinforced concrete (RC) framed structures, various external attachment of corner steel frame configurations was considered as a user-friendly retrofitting method. The external steel frame is designed to contribute to the lateral stiffness and load carrying capacity of the existing RC structure. A six-story building was taken into account. Four different external corner steel frame configurations were suggested in order to strengthen the building. The 3D models of the building with suggested retrofitting steel frames were developed within ABAQUS environment using solid finite elements and analyzed under horizontal loadings nonlinearly. Horizontal top displacement vs loading curves were obtained to determine the overall performance of the building. Contributions of steel and RC frames to the carried loads were computed individually. Load/capacity ratios for the ground floor columns were presented. In the study, 3D rendered images of the building with the suggested retrofits are created to better visualize the real effect of the retrofit on the final appearance of the façade of the building. The analysis results have shown that the proposed external steel frame retrofit configurations increased the lateral load carrying capacity and lateral stiffness and can be used to improve the seismic performance of RC framed buildings.