• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2001.10a
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• pp.132-137
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• 2001

This paper presents a method of seismic analysis for a 2-D fluid-structure-soil interaction systems. With this method, the fluid can be modeled by spurious free 4-node displacement-based fluid elements which use rotational penalty and mass projection technique in conjunction with the one point reduced integration scheme to remove the spurious zero energy modes. The structure and the near-field soil are discretized by the standard 2-D finite elements, while the unbounded far-field soil is represented by the dynamic infinite elements in the frequency domain. Since this method directly models the fluid-structure-soil interaction systems, it can be applied to the dynamic analysis of a 2-D liquid storage structure with complex geometry. Finally, results of seismic analyses are presented for a spent fuel storage tank embedded in a layered half-space and a massive concrete dam on a layered half-space.

• Structural Engineering and Mechanics
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• v.8 no.4
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• pp.411-419
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• 1999

A nonlinear model for time-step analysis of bridges subjected to two orthogonal horizontal components of earthquake motions was developed. The focus of the study was on elastomeric isolators with or without lead cores. The hysteretic behavior of the isolators, the columns, abutments, and shear keys was taken into account. The nonlinear analysis showed that, contrary to linear theory prediction, the use of isolators does not necessarily increase the displacement of the superstructure. Furthermore, it was shown that properly designed isolators can reduce the ductility demand in RC bridge columns substantially.

• Smart Structures and Systems
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• v.12 no.6
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• pp.679-694
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• 2013

In this paper the application of the Interpolation Damage Detection Method to the numerical model of a suspension bridge instrumented with a network of Micro-Electro-Mechanical System sensors is presented. The method, which, in its present formulation, belongs to Level II damage identification method, can identify the presence and the location of damage from responses recorded on the structure before and after a seismic damaging event. The application of the method does not require knowledge of the modal properties of the structure nor a numerical model of it. Emphasis is placed herein on the influence of recorded signals noise on the reliability of the results given by the Interpolation Damage Detection Method. The response of a suspension bridge to seismic excitation is computed from a numerical model and artificially corrupted with random noise characteristic of two families of Micro-Electro-Mechanical System accelerometers. The reliability of the results is checked for different damage scenarios.

• Structural Engineering and Mechanics
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• v.13 no.3
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• pp.241-260
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• 2002

The effect of shear coupled with axial force variation on the inelastic seismic behaviour of reinforced concrete bridge piers is investigated in this paper. For this purpose, a hysteretic axial-shear interaction model was developed and implemented in a nonlinear finite element analysis program. Thus, flexure-shear-axial interaction is simulated under variable amplitude reversed actions. Comparative studies for shear-dominated reinforced concrete columns indicated that a conventional FE model based on flexure-axial interaction only gave wholly inadequate results and was therefore incapable of predicting the behaviour of such members. Analysis of a reinforced concrete bridge damaged during the Northridge (California 1994) earthquake demonstrated the importance of shear modelling. The contribution of shear deformation to total displacement was considerable, leading to increased ductility demand. Moreover, the effect of shear with axial force variation can significantly affect strength, stiffness and energy dissipation capacity of reinforced concrete members. It is concluded that flexure-shear-axial interaction should be taken into account in assessing the behaviour of reinforced concrete bridge columns, especially in the presence of high vertical ground motion.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.05a
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• pp.194-197
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• 2006

This study represents results of fragility curve development for 4-span continuous bridge. 2 type bridge model is chosen frame type and 2-roller 1-hinge type. To research the response of bridge under earthquake excitation, Monte Carlo simulation is performed to study nonlinear dynamic analysis. For nonlinear time history analysis a set of 150 synthetic time histories were generated. Fragility curves in this study are represented by lognormal distribution functions with two parameters and developed as a function of PGA. Five damage states were defined to express the condition of damage based on the actual experimental damage data of bridge column. As a result of this research, the value of damage probability corresponding to each damage state were determined and frame type bridge are favorable under seismic event.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2006.04a
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• pp.733-740
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• 2006

Inverted V (or chevron) braced steel frames have been seen as being highly prone to soft story response once the compression brace buckles under earthquake loading. To salvage chevron braced frames. the concept of the zipper column was proposed many years ago such that the zipper column can redistribute the inelastic demand over the height of the building. However. rational design method for the zipper column has not been established yet. In this paper, a new dynamic design method for the zipper column was proposed by combining the refined physical braced model and modal pushover analysis. Inelastic dynamic analysis conducted on 6 story building model showed that the proposed method was more superior to the existing static design method and was very effective in improving seismic performance of chevron braced steel frames.

• Earthquakes and Structures
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• v.14 no.2
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• pp.95-102
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• 2018

Seismic fragility curves of concrete cylindrical tanks are determined using the finite element method. Vulnerabilities including sloshing of contents, tensile cracking and compression failure of the tank wall due to bending are accounted for. Effects of wall flexibility, fixity at the base, and height-diameter ratio on the response are investigated. Tall, medium and squat tanks are considered. The dynamic analysis is implemented using the horizontal components of consistent earthquakes. The study shows that generally taller tanks are more vulnerable to all of the failure modes considered. Among the modes of failure, the bending capacity of wall was shown to be the critical design parameter.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.11a
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• pp.66-71
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• 2003

The semi-active TLCD system is investigated for control of responses of 3D irregular buildings under seismic excitations. The TLCD system is a special type of TMD system providing a performance similar to a TMD system but offers a number of practical advantages over the traditional TMD system. The equations of motion for the combined building and TLCD system are derived for multistory building structures with rigid floors and plan and elevation irregularities. Simulation results for control of two multistory moment-resisting space structures with vertical and plan irregularities show clearly that the semi-active TLCD control system reduces the responses of 3D irregular buildings subjected to earthquake ground motions efficiently.

• Journal of the Korean Geotechnical Society
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• v.17 no.4
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• pp.15-25
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• 2001

본 고에서는 블록식 보강토 옹벽의 지진시 거동에 관한 유한요소해석 결과를 다루었다. 보강토 옹벽의 지진시 변위거동을 검토한 결과 벽체저부를 지점으로 하는 캔틸레버형태의 변위 거동을 보였으며 따라서 옹벽 상단부에서의 보강재 인장력 증가가 현저하게 나타나 벽체전반에 걸친 분포양상은 균등한 경향을 보였다. 한편, 지진하중으로 인한 증분유발인장력에 관하여 검토한 결과 기존의 보강토 옹벽 내진설계기준과 비교하여 정성.정량적인 측면에서 상당한 차이를 보였으며 내진설계기준이 전반적으로 과소평가 하는 것으로 나타났다. 아울러서, 내진설계측면에서 변위억제 방안에 관한 매개변수 연구결과 임의 조건에 있어서 최대의 보강효과를 나타내는 보강재 임계 강성과 포설길이가 존재하며 최적의 보강효과를 얻기 위해서는 이에 대한 종합적인 검토가 요구되는 것으로 나타났다. 본 고에서는 연구결과를 종합적으로 고찰하여 실무 적용관점에서의 주안점을 언급하였다.

• Proceedings of the Korean Geotechical Society Conference
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• 2009.09a
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• pp.1246-1249
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• 2009

Liquefaction hazard caused by earthquake is the damage in a wide range. Until now, liquefaction hazard potential at a small area or most structure in Korea was assessed by modified Seed & Idriss method. However, it has been known that this method is not proper for metropolitan area due to a lot of time and data to perform the related ground response analyses such as Shake program. For these reasons, the current method has been used facilities or structures, not metropolitan area. In this study, several contents in seismic design of Eurocode and Korean seismic design standard for Port and Harbor were introduced and applied for assessing the liquefaction potential and mapping the liquefaction hazard by LPI(Liquefaction Potential Index). Finally, Ulsan metropolitan city was practically drawn in two dimensional space.