• International Journal of Railway
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• v.7 no.2
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• pp.46-56
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• 2014

The superstructure of the railway track undertakes the forces that develop during train passage and distributes them towards its seating. The track panel plays a key role in terms of load distribution, while at the same time it maintains the geometrical distance between the rails. The substructure and ballast undergo residual deformations under high stresses that contribute to the deterioration of the so-called geometry of the track. The track stiffness is the primary contributing factor to the amount of the stresses that develop on the substructure and is directly influenced by the fastening resilience. Four methods from the international literature are used in this paper to calculate the loads and stresses on the track substructure and the results are compared and discussed. A parametric investigation of the stresses that develop on the substructure of different types of railway tracks (i.e. balastless vs ballasted) is performed and the results are presented as a function of the total static track stiffness.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.05a
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• pp.175-178
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• 2005

The major object of this paper is to propose a nonlinear finite element analysis(FEA) technique of steel coupling beams-wall connections governed panel shear failure using ABAQUS. Detailed finite element models are created by studying the monotonic load response of the designed steel coupling beams-wall connections. The developed models account for the effect of material inelasticity, concrete cracking, panel shear failure and geometric nonlinearity. In order to verify the proposed FEA model, this study attended experiment considered parameters to the steel beam : face bearing plates, and horizontal ties. And the analytical result attended by the proposed FEA model validated through comparisons with the experimental results. Finally, the study estimated the analytical values compared with ASCE Design Guidelines. At this time, the analysis showed good agreement between the theoretical and experimental results.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.05a
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• pp.183-186
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• 2005

The Current design procedures of ACI 318-02 and CEB-FIP for the exterior beam-column joints do not provide engineers with a clear understanding of the physical behavior of the beam-column joints. In this paper, the failure strengths of the exterior beam-column joint specimens tested to failure were evaluated using the approach implementing 3-dimensional strut-tie models, design criteria of ACI 318-02, ACI-ASCE committee 352 and Park and paulay, and softened strut-tie model approach. The analysis results obtained from the 3-dimensional strut-tie models were compared with those obtained from the other approaches, and the validity of the approach implementing 3-dimensional strut-tie models were examined.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.05b
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• pp.509-512
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• 2005

This study try to apply two methodologies which from USACE and RCD research team of Japan on the mix design procedure. Firstly, a basic mix design was decided using the method of USACE. Secondly, the method of Japan RCD research team was adapted to verify the quality. From the results of this study, is impossible to guarantee the quality of RCD using the sieve distribution of the dam concrete chapter in the code of korean. So, it is recommended to apply the guideline of USACE or ASCE on the distribution of aggregate. And, more wide experimental study is necessary to establish the relationsjip between the strength and the compaction ratio, because of the difference of strength according to the ratio of compaction was more than 10$\%$

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2003.10a
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• pp.527-534
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• 2003

This paper presents the LRB-based hybrid base isolation systems employing additional active/semiactive control devices for seismic protection of cable-stayed bridges by examining the ASCE first generation benchmark problem for a cable-stayed bridge. In this study, ideal hydraulic actuators (HAs) and ideal magnetorheological dampers (MRDs) are considered as additional active and semiactive control devices, respectively. Numerical simulation results show that all the hybrid base isolation systems are effective in reducing the structural responses of the benchmark cable-stayed bridge under the historical earthquakes considered. The simulation results also demonstrate that the hybrid base isolation system employing semiactive MRBs is robust to the stiffness uncertainty of the structure, while the hybrid system with active HAs is not. Therefore, the LRB-based hybrid base isolation system employing MRDs could be more appropriate in real applications for full-scale civil infrastructures.

• Computational Structural Engineering
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• v.10 no.1
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• pp.75-80
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• 1997

본 고에서는 구조공학과 관련된 분야에서 유용하게 사용될 수 있는 최근의 통합 자동화 시스템에 대하여 소개하는 내용을 담고 있는 Song Fong Jan 박사가 1994년 6월에 발표한 논문(ASCE Proceedings of the First Congress of Computing in Civil Engineering)을 번역하여 소개한다. 통합 자동화 시스템은 기본적으로 CAD 그래픽 소프트웨어와 지능구조 데이터베이스로 구성되고, 이러한 소프트웨어는 구조물의 모델링과 해석, 설계 및 도면 작성과 합성과정에서 통합적인 운용이 가능하도록 사용된다. 현재 사용되고 있는 여러가지 상업용 구조설계용 소프트웨어를 통합함으로써 구조물 설계분야에 보다 효율적인 시스템을 만들 수 있을 것이다. 여기서는 여러가지 다양한 시스템을 사용할 때의 장단점이나 적절한 프로그램 검증과 품질의 확보문제 그리고 구조공학 자동화분야의 미래 발전방향에 대하여 논의해 보고자 한다.

• Earthquakes and Structures
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• v.7 no.5
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• pp.877-890
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• 2014

The purpose of this study is to present adequate modeling solutions for squat and slender RC walls. ASCE41-13 (American Society of Civil Engineers) specifies that the aspect ratios of height to width for the RC walls affect the hysteresis response. Thus, this study performed non-linear analysis subjected to cyclic loading using two different macroscopic models: one of macroscopic models represents flexural failure of RC walls (Shear Wall Element model) and the other (General Wall Element model) reflects diagonal shear failure occurring in the web of RC walls. These analytical results were compared to previous experimental studies for a slender wall (> aspect ratio of 3.0) and a squat wall (= aspect ratio of 1.0). For the slender wall, the difference between the two macroscopic models was negligible, but the squat wall was significantly affected by parameters for shear behavior in the modeling method. For accurate performance evaluation of RC buildings with squat walls, it would be reasonable to use macroscopic models that give consideration to diagonal shear.

• Structural Engineering and Mechanics
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• v.45 no.6
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• pp.821-835
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• 2013

The acceleration that the electrical equipment experiences on a structure can be several times the ground acceleration. Currently, substation support structures are being designed according to ASCE (Substation Structure Design Guide 2008), without any consideration about effects of these structures on dynamic behavior of mounted equipment. In this paper, a parametric study is implemented in order to improve seismic design of candlestick substation structures based on this design guide. To do this, dynamic amplification factor (DAF) of different candlestick support-equipment combinations is evaluated and compared to the target DAF presented in IEEE STD 693 (2006). Based on this procedure, a new criterion is developed to restrict maximum acceleration at support-equipment intersection.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2002.04a
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• pp.149-156
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• 2002

This paper examines the ASCE first generation benchmark problem for a seismically excited cable-stayed bridge, and proposes a new semi-active control strategy focusing on inclusion of effects of control- structure interaction. In this study, magnetorheological (MR) fluid dampers, which belong to the class of controllable fluid dampers, are proposed as the supplemental damping devices, and a clipped-optimal control algorithm, shown to perform well in previous studies involving MR fluid dampers, is employed. The dynamic model for MR fluid dampers is considered as a modified Bouc-Wen model, which is obtained from data based on experimental results for large-scale dampers. Numerical results show that the performance of the proposed semi-active control strategy using MR fluid dampers is quite effective.

• Proceedings of the Korea Concrete Institute Conference
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• 2004.11a
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• pp.405-408
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• 2004

The current design procedures of ACI 318-02, CE3-FIP and NZS 3101 for interior beam-column joints do not provide engineers with a clear understanding of the physical behavior of beam-column joints. In this paper, the failure strengths of the interior beam-column joint specimens tested to failure were evaluated using the 3-dimensional strut-tie model approach, design criteria of ACI 318-02, ACI-ASCE committee 352 and Park and paulay, and softened strut-tie model approach. The analysis results obtained from the 3-dimensional strut-tie model approach were compared with those obtained from the other approaches, and the validity of the approach implementing a 3-dimensional strut-tie model was examined.