• Structural Engineering and Mechanics
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• v.41 no.1
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• pp.83-94
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• 2012

Assessment of a monumental concrete arch bridge with a total length of 210 meters having three major spans of 30 meters and a height of 65 meters, which is located in an earthquake-prone region in southern part of the country is presented in this study. Three-dimensional finite element model of the bridge was generated using a commercially available general finite element analysis software and based on the outcomes of a series of in-depth acceleration measurements that were conducted on-site, the model was refined. By using the structural parameters obtained from the dynamic and the static tests, calibrated model of the bridge structure was obtained and this model was used for necessary calculations regarding structural assessment and evaluation.

• Journal of the Korean Society of Propulsion Engineers
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• v.5 no.3
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• pp.1-9
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• 2001

Impact tests are performed on the high strength structural steel that is being developed for the submarine material. Especially, the impact characteristics of this structural steels at low temperatures are investigated by charpy impact testing. Hyperbolic tangent curve fitting method is used to evaluate the LSE(lower shelf energy), USE(upper shelf energy) and DBTT(ductile-brittle transition temperature). Proportional equations between charpy impact energy and lateral expansion are obtained using the test results. Effect of temperature on the fracture appearance is investigated by using SEM.

• Journal of the Korean Society for Railway
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• v.3 no.2
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• pp.43-50
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• 2000

The corrugated panels are the prime candidate structure for the floor, roof and wall of Korean high speed train. The equivalent continuum modeling approach panels can be used for the efficient design and evaluation of their structural characteristics. The equivalent continuum models, derived from the true complex corrugated panels, should have the same structural behavior as the original structures have. This paper briefly reviews three representative continuum modeling methods: the static analysis method and two plate-models based on modal analysis methods (MAM). These methods are evaluated through some numerical examples by comparing the natural frequencies and static deflections. It is observed that the plate-model based on Rayleigh-Ritz method seems to provide the best results when used in conjunction with the cantilever-type boundary conditions. The equivalent elastic constants of various corrugated panels, depending on the changes in their configurations, are tabulated for efficient use in structural design.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2002.04a
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• pp.53-60
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• 2002

It has been recognized that damage control must become a more explicit design consideration. In an effort to develop design methods based on performance it is clear that the evaluation of the inelastic response is required. The methods available to the design engineer today are nonlinear time history analyses, or monotonic static nonlinear analyses, or equivalent static analyses with simulated inelastic influences. Some codes proposed the capacity spectrum method based on the nonlinear static(pushover) analysis to determine earthquake-induced demand given the structure pushover curve. This procedure is conceptually simple but iterative and time consuming with some errors. This paper presents a nonlinear direct spectrum method to evaluate seismic Performance of structure, without iterative computations, given the structural initial elastic period and yield strength from the pushover analysis, especially for multi degree of freedom structures. The purpose of this paper is to investigate accuracy and confidence of this method from a point of view of various earthquakes and unloading stiffness degradation parameters.

• Computational Structural Engineering
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• v.7 no.4
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• pp.137-144
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• 1994

As for the safety evaluation of existing large-scale structures, methods for the estimation of structural and dynamic properties are studied. Sequential prediction error method in time domain and frequency response function estimators in frequency domain are examined. For this purpose, impact tests are performed on a steel frame structure with 2 bays and 3 floors. Results from both methods are found to be consistent to each others. However those from the finite-element analysis are slightly different from the experimental results. The discrepancies may be caused by the improper modeling of the complex behavior at the connection joints of the model structure.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2010.04a
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• pp.700-703
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• 2010

일반적으로 구조부재의 안전성 평가는 계측된 센서의 변형률로부터 부재의 최대응력 또는 부재력 수준을 결정하고 설계기준에 의한 부재의 허용응력 또는 설계 강도와의 비교에 의해서 이루어진다. 그러나 이러한 설계기준은 건물의 설계단계에서 미리 가정된 하중 및 부재의 강도에 대한 여러 확률분포 또는 안전율을 반영하여 작성된 것으로 실질적으로 센서로부터 측정한 데이터를 직접 설계기준에 반영하는 것은 합리적이지 못하다. 본 연구에서는 실제 센서로부터 측정되는 변형률을 이용하여 합리적으로 구조부재의 안전성 평가를 수행하기 위한 방법을 모색하고자 한다. 설계기준을 고려한 변형률 제한치, 저감계수가 도입되었으며 이에 추가적으로 센서와 관련한 계수를 도입하여 구조부재의 안전성 평가를 위한 방향을 제시한다.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2010.04a
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• pp.243-246
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• 2010

본 연구에서는 초고층 건물의 구조시스템에 대한 다양한 대안으로부터 각 대안의 성능을 합리적으로 평가하는 방법을 연구하였다. 이를 위해 우선, 대안평가를 위한 평가항목과 각 평가항목별 평가기준을 도출하고, 도출된 기준에 따라 평가결과를 산정하는 방법을 제안하였다. 그리고 평가항목간의 관계와 평가항목의 중요도를 산정하고, 퍼지적분을 이용하여 평가결과를 종합화하는 방안을 제안하였다. 평가항목은 크게 세가지로 이에는 구조성능, 경제성, 공기가 있다. 대안에 대한 평가는 예비평가, 본평가, 실시평가의 세 단계로 이루어지며, 각각 보수적인 관점에서와 낙관적인 관점에서의 평가를 실시하고 주어진 평가결과를 바탕으로 최종적으로는 엔지니어가 대안을 선정하는 방향으로 평가를 진행한다.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2010.04a
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• pp.255-258
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• 2010

최근 초고층 구조물은 다양한 형태에 따른 건축 계획 및 설계에 대한 요구되어지며 이를 충족시키기 위해 다양한 구조시스템이 개발되어지고 있다. 특히 경사기둥은 구조물의 높이가 증가할수록 구조물의 면적이 점차적으로 감소하는 Tapered 형태의 비정형 초고층 구조물의 중요한 설계 및 구조요소이다. 본 논문에서는 경사기둥의 축하중에 의해 발생하는 수평력으로 인한 접합부의 영향 및 보 플랜지의 취성파괴에 대한 저항성능을 평가하기 위하여 강구조물 경사기둥 접합부에 대한 유한요소해석을 수행하였다.

• Journal of Fisheries and Marine Sciences Education
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• v.29 no.2
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• pp.544-551
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• 2017

Metaheuristic algorithms are efficient techniques for a class of mathematical optimization problems without having to deeply adapt to the inherent nature of each problem. They are very useful for structural design optimization in which the cost of gradient computation can be very expensive. Among them, the characteristics of simulated annealing and genetic algorithms are briefly discussed. In Metropolis genetic algorithm, favorable features of Metropolis criterion in simulated annealing are incorporated in the reproduction operations of simple genetic algorithm. Numerical examples of structural design optimization are presented. The example structures are truss, breakwater and steel box girder bridge. From the theoretical evaluation and numerical experience, performance and applicability of metaheuristic algorithms for structural design optimization are discussed.

• Proceedings of the Korea Concrete Institute Conference
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• 1990.10a
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• pp.41-44
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• 1990

There is the need to balance safety, economy and serviceability in all phases of society proboems. This is especially true in structural code formulation, where a framework is established by which practicing structural enginers can be assured of designing structures that reasonably meet the above three objectives. The existeing design codes, which are generally based on the structural theory and certain engineering experience, do not realistically consider the uncertainties of loads and resistances and the basic reliability concepts. The purpose of the present study is therefore to develop the realistic reliablility-based design criteria to secure adequate safety and reliability, and to derive the models for partial and combined resistance factor formats.