• 한국구조물진단유지관리공학회 논문집
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• 제21권6호
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• pp.91-97
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• 2017

본 연구는 중공 슬래브의 보다 정확한 동특성을 구하기 위하여 중공부분에 의한 단면손실 효과를 반영한 해석모델을 이용한 모드해석결과와 가진실험 및 계측 결과를 비교 검토하였다. 이를 위해 중공 슬래브의 일종인 오메가형 데크 슬래브를 적용한 실제 시공 현장에서 가진실험 실시하여 계측을 통해 중공 슬래브의 동특성을 구하였다. 실제 중공 부분의 단면 감소효과를 고려하여 해석모델을 산정하여 모드해석을 수행하였다. 해석모델을 이용한 모드해석결과와 가진실험 계측결과를 비교 분석한 결과, 진동수의 경우 가진실험 계측과와의 오차가 2~7% 이내에 있음을 확인하였다. 그 결과 해석모델을 이용한 해석결과가 중공 슬래브의 진동해석에 충분한 정확도를 가지고, 슬래브 사용성 검토에 적용될 수 있음을 확인하였다.

• Wind and Structures
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• 제10권6호
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• pp.543-554
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• 2007

The suspension bridge is situated in an area of complex topography with both open sea and overland turbulence characteristics, and it is subject to frequent typhoon occurrences. This paper investigates experimentally the possible vortex shedding events of the structure under high wind and typhoon conditions. A single-degree-of-freedom model for the vibration of a unit bridge deck section is adopted to determine the amplitude of vibration and to estimate the parameters related to the lifting force in a vortex shedding event. The results of the studies are presented in a companion paper (Law, et al. 2007). In this paper, statistical analysis on the measured responses of the bridge deck shows that the vibration response at the first torsional mode of the structure has a significant increase at and beyond the critical wind speed for vortex shedding as noted in the wind tunnel tests on a section model of the structure.

• Steel and Composite Structures
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• 제2권2호
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• pp.147-160
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• 2002

This paper summarises results of the research performed at the Department of Steel Structures and Structural Mechanics from the "Politehnica" University of Timisoara, Romania, in order to evaluate the performance of beam-to-column extended end plate connections for steel and composite joints. It comprises laboratory tests on steel and composite joints, and numerical modelling of joints, based on tests. Tested joints are double-sided, with structural elements realised of welded steel sections. The columns are of cruciform cross-section, while the beams are of I section. Both monotonic and cyclic loading, symmetrically and antisymmetrically, has been applied. On the basis of tested joints, a refined computer model has been calibrated using a special connection element of the computer code DRAIN 2DX. In this way, a static/dynamic structural analysis of framed structures with real characteristics of the beam to column joints is possible.

• 한국강구조학회 논문집
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• 제21권1호
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• pp.63-70
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• 2009

파괴모드는 저항력과 비탄성 변형 능력의 저하를 일으키는 균열이나 파단으로 귀결된다. 특수중심가새골조의 잠재적 파괴모드는 가새의 균열이나 파단, 가새나 거싯 플레이트의 순단면 파단, 거싯 플레이트용접의 균열, 볼트의 전단균열, 블록전단파단, 그리고 거싯 플레이트의 좌굴 등을 포함하고 있다. HSS 튜브가새는 특수중심가새골조에 자주 사용되고, 가새의 순단면 파단은 거싯 플레이트가 가새로 삽입되는 홈의 끝부분에 가새의 순단면을 통해 발생한다. 이 파괴모드는 인장파괴모드로 분류되고 급격한 강도저하와 취성적인 거동을 보인다. AISC 디자인 규준에선 순단면 보강을 요구하고 있다 (AISC 2001). 이 논문에서, 순단면 보강의 필요성에 대해 논의한다. 먼저, 미국 버클리대학교에서 수행됐던 순단면 파단실험을 유한요소모델을 이용한 이 실험의 모델링을 통해 소개한다. 실제 골조에서의 순단면 파단의 가능성을 조사하기 위해, 홈이 있는 중심가새골조를 유한요소법을 이용 모델링 하고, 인장지배의 근거리지진 이력을 적용시킨다. 이는 이력이 순단면 파단의 가장 중요한 인자라는 이전 해석 결과에서 기인한 것이다. 순단면 보강의 필요성과 인장지배의 근거리지진 이력의 영향에 대해 조사한다.

• 한국농공학회:학술대회논문집
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• 한국농공학회 1999년도 Proceedings of the 1999 Annual Conference The Korean Society of Agricutural Engineers
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• pp.465-472
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• 1999

Hydraulic model tests are performed to find economical and hdrqulically stable design of cooling water intake channel of steam power plant. The result of tests show that the standard distributiion of y-components in the chamber of CWP(circulating Water Pump) are recommended below 3.5 to maintain hydraulic stability, so that this value is considered as the design criteria. Common basin is necessary to improve the hydraulic stability of inflow, however the longer basin does not always improve the hydraulic stability , and the optimal length of basin can be found in some range. From the results the flow stability maintained the best condition when the length of basin is 7.2m. Beside the standard tests the auxiliary tests like edge , baffle, trapezoidal section and increase of pump capacity are carried out based on the optimal condition foudn in the standard tests. From the series of tests the economical and hydraulically stable design of intake channel was proposed.

• Steel and Composite Structures
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• 제19권6호
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• pp.1403-1419
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• 2015

When precast concrete infill panels are connected to steel frames at discrete locations, interaction at the structural interface is neither complete nor absent. The contribution of precast concrete infill panels to the lateral stiffness and strength of steel frames can be significant depending on the quality, quantity and location of the discrete interface connections. This paper presents preliminary experimental and finite element results of an investigation into the composite behaviour of a square steel frame with a precast concrete infill panel subject to lateral loading. The panel is connected at the corners to the ends of the top and bottom beams. The Frame-to-Panel-Connection, FPC4 between steel beam and concrete panel consists of two parts. A T-section with five achor bars welded to the top of the flange is cast in at the panel corner at a forty five degree angle. The triangularly shaped web of the T-section is reinforced against local buckling with a stiffener plate. The second part consists of a triangular gusset plate which is welded to the beam flange. Two bolts acting in shear connect the gusset plate to the web of the T-section. This way the connection can act in tension or compression. Experimental pull-out tests on individual connections allowed their load deflection characteristics to be established. A full scale experiment was performed on a one-storey one-bay 3 by 3 m infilled frame structure which was horizontally loaded at the top. With the characteristics of the frame-to-panel connections obtained from the experiments on individual connections, finite element analyses were performed on the infilled frame structures taking geometric and material non-linear behaviour of the structural components into account. The finite element model yields reasonably accurate results. This allows the model to be used for further parametric studies.

• Steel and Composite Structures
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• 제16권4호
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• pp.437-454
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• 2014

The influence of spacers on the behaviour and ultimate capacity of intermediate length CFS open section columns under axial compression is investigated in this paper. The focus of the research lies in the cross- section predominantly, failed by distortional buckling. This paper made an attempt to either delay or eliminate the distortional buckling mode by the introduction of transverse elements referred herein as spacers. The cross-sections investigated have been selected by performing the elastic buckling analysis using CUFSM software. The test program considered three different columns having slenderness ratios of 35, 50 & 60. The test program consisted of 14 pure axial compression tests under hinged-hinged end condition. Models have been analysed using finite element simulations and the obtained results are compared with the experimental tests. The finite element package ABAQUS has been used to carry out non-linear analyses of the columns. The finite element model incorporates material, geometric non-linearities and initial geometric imperfection of the specimens. The work involves a wide parametric study in the column with spacers of varying depth and number of spacers. The results obtained from the study shows that the depth and number of spacers have significant influence on the behaviour and strength of the columns. Based on the nonlinear regression analysis the design equation is proposed for the selected section.

• 한국도로학회논문집
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• 제11권2호
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• pp.17-25
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• 2009

본 연구의 목적은 사고위치별(유입부, 유출부, 교차로내 및 횡단보도) 로지스틱 회귀 교통사고 모형을 개발하는 것이다. 충북지방경찰청의 2004$\sim$2005년도 사고 자료와 현장조사 자료를 근거로, 교통사고와 관련된 기하구조 요소, 환경 요소 등이 분석되었다. 개발된 모형은 카이제곱 p 값은 0.000 그리고 Nagelkerke $R^2$값 0.363$\sim$0.819로 모두 통계적으로 유의한 것으로 분석된다. 개발된 모형의 공통 사고요인은 교통량, 횡단거리 및 좌회전전용차로이며, 특정변수는 교차로내 사고모형의 부도로 교통량, 그리고 횡단보도 사고모형의 주도로 U턴인 것으로 나타나고 있다. Hosmer & Lomeshow 검정은 유입부를 제외한 모형들은 p값이 0.05보다 크기 때문에 통계적으로 적합한 것으로 평가된다. 또한 정분류율 결과는 모든 모형식이 73.9% 이상으로 높은 예측력을 보이는 것으로 분석된다.

• Geomechanics and Engineering
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• 제4권3호
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• pp.173-190
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• 2012

With recent growing interests in the Performance-Based Seismic Design and Assessment Methodology, more realistic modeling of a structural system is deemed essential in analyzing, designing, and evaluating both newly constructed and existing buildings under seismic events. Consequently, a shallow foundation element becomes an essential constituent in the implementation of this seismic design and assessment methodology. In this paper, a contact interface fiber section element is presented for use in modeling soil-shallow foundation systems. The assumption of a rigid footing on a Winkler-based soil rests simply on the Euler-Bernoulli's hypothesis on sectional kinematics. Fiber section discretization is employed to represent the contact interface sectional response. The hyperbolic function provides an adequate means of representing the stress-deformation behavior of each soil fiber. The element is simple but efficient in representing salient features of the soil-shallow foundation system (sliding, settling, and rocking). Two experimental results from centrifuge-scale and full-scale cyclic loading tests on shallow foundations are used to illustrate the model characteristics and verify the accuracy of the model. Based on this comprehensive model validation, it is observed that the model performs quite satisfactorily. It resembles reasonably well the experimental results in terms of moment, shear, settlement, and rotation demands. The hysteretic behavior of moment-rotation responses and the rotation-settlement feature are also captured well by the model.

• Geomechanics and Engineering
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• 제32권6호
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• pp.601-613
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• 2023

Low liquid limit silt, widely distributed in the middle and down reaches of Yellow River, has the disadvantages of poor grading, less clay content and poor colloidal activity. It is very easy to cause vehicle jumping at the bridge-embankment transition section when the low liquid limit silt used as the backfill at the abutment back. In this paper, a series of laboratory tests were carried out to study the physical and mechanical properties of the low liquid limit silt used as back filling. Ground granulated blast furnace slag (GGBFS) was excited by active MgO and hydrated lime to solidify silt as abutment backfill. The optimum ratio of firming agent and the compaction and mechanical properties of reinforced soil were revealed through compaction test and unconfined compressive strength (UCS) test. Scanning electron microscope (SEM) test was used to study the pore characteristics and hydration products of reinforced soil. 6% hydrated lime and alkali activated slag were used to solidify silt and fill the model of subgrade respectively. The pavement settlement regulation and soil internal stress-strain regulation of subgrade with different materials under uniformly distributed load were studied by model experiment. The effect of alkali activated slag curing agent on curing silt was verified. The research results can provide technical support for highway construction in silt area of the Yellow River alluvial plain.