• Steel and Composite Structures
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• 제4권2호
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• pp.77-94
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• 2004

Steel beam-to-column joints are often subjected to a combination of bending and axial forces. The level of axial forces in the joint may be significant, typical of pitched-roof portal frames, sway frames or frames with incomplete floors. Current specifications for steel joints do not take into account the presence of axial forces (tension and/or compression) in the joints. A single empirical limitation of 10% of the beam's plastic axial capacity is the only enforced provision in Annex J of Eurocode 3. The objective of the present paper is to describe some experimental and numerical work carried out at the University of Coimbra to try to extend the philosophy of the component method to deal with the combined action bending moment and axial force.

• 한국지역지리학회지
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• 제22권2호
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• pp.369-382
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• 2016

본 연구는 제주도 촌락 가옥의 유형과 특성을 고찰하는 연구이다. 제주도 촌락 가옥의 유형을 지붕 형태, 지붕 재료, 외벽 재료를 중심으로 고찰하고, 경남 촌락 가옥의 유형과 비교하면서 그 특성을 논의한다. 이러한 촌락 가옥에 대한 연구는 오늘날의 촌락 경관을 이해하기 위하여 반드시 필요한 연구라고 본다. 제주도 촌락 가옥에서는 우진각지붕이나 우진각지붕/평지붕의 지붕 형태가 가장 많고, 그 다음으로는 단순평지붕 맞배지붕 눈썹평지붕 등의 지붕 형태가 다수를 차지한다. 그리고 컬러강판, 인조슬레이트, 시멘트, 기와/시멘트, 슬레이트/시멘트 등의 지붕 재료 사용 빈도가 높다. 외벽 재료에서는 시멘트를 단일 재료로 사용한 가옥이 과반수를 차지하고, 그 다음으로 현무암석재/시멘트, 타일/시멘트, 타일, 사이딩 등을 사용한 가옥이 많다. 제주도 촌락 가옥은 지붕 형태와 외벽 재료의 특성이라는 측면에서 경남 촌락 가옥과 사뭇 다른 특성을 나타낸다. 제주도 촌락 가옥의 가장 두드러지는 특성으로는 우진각지붕 가옥이 매우 많다는 점, 팔작지붕 가옥이 매우 희귀하다는 점, 현무암석재를 외벽 재료로 사용한 가옥이 많다는 점 등을 들 수 있다.

• Geomechanics and Engineering
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• 제28권3호
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• pp.209-224
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• 2022

In this study, the numerical analysis model of π-beam explosion is established to compare and analyze the failure modes of the π-beam under the action of explosive loads, thus verifying the accuracy of the numerical model. Then, based on the numerical analysis of different protection forms of π beams under explosive loads, the peak pressure of π beam under different protection conditions, the law of structural energy consumption, the damage pattern of the π beam after protection, and the protection efficiency of different protective layers was studied. The testing results indicate that the pressure peak of π beam is relatively small under the combined protection of steel plate and aluminum foam, and the peak value of pressure decays quickly along the beam longitudinal. Besides, as the longitudinal distance increases, the pressure peak attenuates most heavily on the roof's explosion-facing surface. Meanwhile, the combined protective layer has a strong energy consumption capacity, the energy consumed accounts for 90% of the three parts of the π beam (concrete, steel, and protective layer). The damaged area of π beam is relatively small under the combined protection of steel plate and aluminum foam. We also calculate the protection efficiency of π beams under different protection conditions using the maximum spalling area of concrete. The results show that the protective efficiency of the combined protective layer is 45%, demonstrating a relatively good protective ability.

• Structural Engineering and Mechanics
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• 제49권2호
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• pp.237-259
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• 2014

Wind-induced failure around screwed connections has been documented in roof and wall cladding systems made with steel sheet cold-formed panels during high wind events. Previous research has found that low cycle fatigue caused by stress concentration and fluctuating wind loads is responsible for most such failures. A dynamic load protocol was employed in this work to represent fatigue under wind effects. A finite element model and fatigue criteria were implemented and compared with laboratory experiments in order to predict the fatigue failure associated with fluctuating wind loads. Results are used to develop an analytical model which can be employed for the fatigue analysis of steel cold-formed cladding systems. Existing three dimensional fatigue criteria are implemented and correlated with fatigue damage observed on steel claddings. Parametric studies are used to formulate suitable yet simple fatigue criteria. Fatigue failure is predicted in different configurations of loads, types of connections, and thicknesses of steel folded plate cladding. The analytical model, which correlated with experimental results reported in a companion paper, was validated for the fatigue life prediction and failure mechanism of different connection types and thicknesses of cold-formed steel cladding.

• 한국지역지리학회지
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• 제21권4호
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• pp.660-672
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• 2015

촌락 가옥은 촌락 경관을 구성하는 중요한 요소이다. 기존의 촌락 가옥에 대한 지리학 연구는 주로 전통적인 민가에 초점을 두었으나, 본 연구는 오늘날의 촌락 가옥에 초점을 둔다. 본 연구는 경남 도서지역 가옥의 지붕 형태와 지붕 재료를 중심으로 제시하는 촌락 가옥의 유형에 관한 연구이다. 연구지역의 가옥에 대한 조사 결과를 바탕으로 해서 지붕 형태와 지붕 재료를 분류하는 기준을 제시하고, 이에 따른 촌락 가옥의 유형화를 시도한다. 지붕 형태를 중심으로 분류하는 가옥 유형에서는 팔작지붕 우진각 맞배지붕과 같은 전통적인 지붕 형태를 가진 가옥이 많고, 전통적인 지붕 형태 이외의 가옥 유형에서는 단순평지붕 가옥이 많다. 두 개 이상의 지붕 형태를 가진 결합양식지붕 가옥 유형의 경우, 경사-평지붕 가옥이 경사-경사지붕 가옥보다 10여 배나 많다. 지붕 재료 중에서는 시멘트, 컬러강판, 인조슬레이트가 가장 많이 사용된다. 특정 지붕 재료가 특정 지붕 형태에서 두드러지게 사용되는 경우가 있는데, 이를 통해 연구지역의 주요한 가옥 유형을 '지붕 재료와 지붕 형태'를 중심으로 다섯 가지로 유형화할 수 있다.

• Fisheries and Aquatic Sciences
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• 제3권1호
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• pp.1-7
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• 2000

Different substrata fixed as the roof (for shadow) on artificial iron reef had been developed as a tool for valuable fishery resources. The experiment was set up on a sandy bottom substratum at 8m depth in Muronohana, Ikata, Japan. Within one month of placement of the plates, diatoms dominated the experimental plates with a coverage of $100\%$ approximately. Enteromorpha intestinalis and Colpomenia sinuosa dominated within three months after the placement. E. intestinalis coverage on substrata was estimated $7\%$ on the plate shaped iron bar, $12-14\%$ on concrete plates, $18\%$ on the plate fixed pebble, $61\%$ on the plate to accumulated wood, and 80-100% on the steel materials plate. Whereas after four months of placement, C. sinuosa coverage on plates became $1-36\%$ on different plates, and $100\%$ on the plate to accumulated wood. The differences in E. intestinalis and C. sinuosa colonization on the different substrata were probably due to variations in their surface roughness influencing the settlement of zoospores, and thus gametophyte. development. After five months of placement, the above two species slowly disappeared.

• 국제초고층학회논문집
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• 제1권4호
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• pp.271-281
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• 2012

Tianjin Goldin Finance 117 tower has an architectural height of 597 m, total of 117 stories, and the coronation of having the highest structural roof of all the buildings under construction in China. Structural height-width ratio is approximately 9.5, exceeding the existing regulation code significantly. In order to satisfy earthquake and wind-resisting requirements, a structure consisting of a perimeter frame composed of mega composite columns, mega braces and transfer trusses and reinforced concrete core containing composite steel plate wall is adopted. Complemented by some of the new requirements from the latest Chinese building seismic design codes, design of the super high-rise building in high-intensity seismic area exhibits a number of new features and solutions to professional requirements in response spectrum selection, overall stiffness control, material and component type selection, seismic performance based design, mega-column design, anti-collapse and stability analysis as well as elastic-plastic time-history analysis. Furthermore, under the prerequisite of economic viability and a series of technical requirements prescribed by the expert review panel for high-rise buildings exceeding code limits, the design manages to overcome various structural challenges and realizes the intentions of the architect and the client.

• Structural Engineering and Mechanics
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• 제54권1호
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• pp.149-168
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• 2015

In the bolted connections, bolt placements are generally described and are generally made in the direction of design effects and in the perpendicular direction to design effects. In these both directions, the reliability of the distance of bolts to the edges of connection plate and the distance of bolts to each other is investigated for high strength steel connections built up with high strength bolts in this study. For this purpose, simple SL (bearing type shear connection) and SLP (bearing type shear connection for body-fit bolts) type steel connections with St 52 grade steel plates with 8 different thicknesses and with 8.8D grade high strength bolts (HV) were constituted and analyzed under H (Dead Loads+Live Loads+Snow Loads+Roof Loads) and HZ (H Loads+Wind Loads+Earthquake Loads) loadings. Geometric properties, material properties and design actions were taken as random variables. Monte Carlo Simulation method was used to compute failure risk and the first order second moment method was used to determine the reliability indexes of those different distances describing the placement of bolts. Results obtained from computations have been presented in graphics and in a Table. Then, they were compared with some values proposed by some structural codes. Finally, new equations were constituted for minimum and maximum values of distances describing bolt placement by regression analyses performed on those results.

• Earthquakes and Structures
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• 제16권1호
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• pp.83-96
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• 2019

The seismic behavior of PRC coupling beam-hybrid coupled shear wall system is analyzed by using the finite element software ABAQUS. The stress distribution of steel plate, reinforcing bar in coupling beam, reinforcing bar in slab and concrete is investigated. Meanwhile, the plastic hinges developing law of this hybrid coupled shear wall system is also studied. Further, the effect of coupling ratio, section dimensions of coupling beam, aspect ratio of single shear wall, total height of structure and the role of slab on the seismic behavior of the new structural system. A fitting formula of plate characteristic values for PRC coupling beams based on different displacement requirements is proposed through the experimental date regression analysis of PRC coupling beams at home and abroad. The seismic behavior control method for PRC coupling beam-hybrid coupled shear wall system is proposed based on the continuous connection method and through controlling the coupling ratio, the roof displacement, story drift angle of hybrid coupled shear wall system, displacement ductility of coupling beam.

• 한국지진공학회논문집
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• 제21권6호
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• pp.311-322
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• 2017

In this study, the seismic performance of concrete-steel composite moment frame structures equipped with seismic retrofitting systems such as seismic reinforcement, base isolators, and bracing members, which are typical earthquake damage mitigation systems, is evaluated through nonlinear dynamic analyses. A total of five frame models were designed and each frame model was developed for numerical analyses. A total of 80 ground acceleration data were used to perform the nonlinear dynamic analysis to measure ground shear force and roof displacement, and to evaluate the behavioral performance of each frame model by measuring inter-story drift ratios. The analysis results indicate that the retrofitting device of the base isolator make a significant contribution to generating relatively larger absolute displacement than other devices due to flexibility provided to interface between ground and column base. However, the occurrence of the inter-story drift ratio, which is a relative displacement that can detect the damage of the structure, is relatively small compared with other models. On the other hand, the seismic reinforced frame model enhanced with the steel plate at the lower part of the column was found to be the least efficient.