• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.15 no.12 s.105
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• pp.1340-1346
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• 2005

In this study, based on shaking table test results on a seismically isolated bridge model, an inelastic numerical model is refined by using Bouc-Wen model representing the hysteretic behavior of isolators. Seismic responses of isolated bridges are numerically investigated varying with relative stiffness ratio(RSR), which is a ratio of the effective stiffness of isolator to the lateral stiffness of bridge pier, From the results, it is found that an adequate range of relative stiffness ratio could be defined for seismic design of isolated bridges without considering the flexibility of piers.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2007.04a
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• pp.545-550
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• 2007

Due to many advantages such as lightweight, high durability and speedy construction, increasing number of bridges of various girder types are being built recently with glass-fiber reinforced composite deck. A profile of the composite deck, called 'Delta deck', is developed which has 3 trapezoidal cells of 200mm depth. This paper introduces how to develop 'Delta deck' and its application to the world largest composite-deck bridge, which is 300m long and 35m wide and is currently under construction.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 1999.04a
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• pp.231-238
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• 1999

The longitudinal dynamic behaviors of the bridge system consisting of multiple simply supported spans under seismic excitations are examined considering pounding effects. The pounding phenomena between adjacent girders which may consequently result in the span collapses are modeled by using the multi-degree-of-freedom system, The inelastic behavior of the RC pier is also considered by adopting the hysteresis loop model and the p-$\delta$ effect. Motions of the foundation and abutment are also considered but the local damage resulting from the girder pounding assumed to be neligible. The developed model is found to give the appropriate information of the dynamic characteristics of the bridge behavior. It is observed that the pounding effect becomes significant as the peak acceleration of the seismic excitation increases. Under minor earthquakes the pounding tends to increase the relative displacements while under strong earthquakes it tends to decrease the relative displacements by restricting the longitudinal girder motions, therefore it is suggested that the pounding effects should be considered in the analysis of the relative displacements of the longitudinally adjacent girder motions.

• Proceedings of the Korea Concrete Institute Conference
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• 2004.11a
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• pp.663-666
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• 2004

An analysis of the annual frequency of collapse(AF) is performed for each bridge pier exposed to ship collision. AF is computed for each bridge component and vessel classification. The summation of AFs computed over all of the vessel classification intervals for a specific component should equal the annual frequency of collapse of the component. The designer should use judgment in developing a distribution of the vessel frequency data based on discrete groupings or categories of vessel size by DWT. In the present study the effect of vessel classification on the annual frequency of collapse in the ship collision risk assessment is investigated by illustrative numerical examples based on the vessel frequency data of the domestic harbor. The DWT interval for larger vessels has more effect on the ship collision risk. Therefore the expert judgement in determining the larger DWT interval is required because the design impact lateral resistances of bridge components depend on the ship collision risk.

• Coupled systems mechanics
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• v.3 no.2
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• pp.213-232
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• 2014

Pounding is a major cause of bridge damage during earthquakes. In an extreme situation, it can even contribute to the unseating of bridge girders. Long-span bridges will inevitably experience spatially varying ground motions. Soil-structure interaction (SSI) may play a significant role in the structural response of these structures. The objective of this research is to experimentally investigate the effect of spatially varying ground motions on the response of a three-segment bridge considering SSI and pounding. To incorporate SSI, the model was placed on sand contained in sandboxes. The sandboxes were fabricated using soft rubber in order to minimise the rigid wall effect. The spatially varying ground motion inputs were simulated based on the New Zealand design spectra for soft soil, shallow soil and strong rock conditions, using an empirical coherency loss function. The results show that with pounding, SSI can amplify the pier bending moments and the relative opening displacements.

• Journal of The Korean Society of Agricultural Engineers
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• v.46 no.1
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• pp.61-71
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• 2004

The performance evaluation and deflection of 3 spans concrete simplicity slab bridge analyzed by non-destructive and loading test. Compressive strength of slab and pier appeared in the range of each 353∼366 kgf/$cm^2$ and 152∼215 kgf/$cm^2$ in rebound number test. Also, it appeared that concrete quality of slab was good after performance improvement. The average compressive strength of slab by core picking appeared 229 kg/$cm^2$. In reinforcing bar arrangement test of span and member, it appeared that horizontal and vertical reinforcing bar was arranged to fixed interval. The value of calculation deflection that carried structural analysis with deflection analysis wave in static loading test appeared higher than that of experimental deflection and it appeared that hardness of this bridge was good. Maximum impact factor that estimated from deflection by running speed in dynamic loading test appeared by 0.216 in 10 km/hr running speed.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.11a
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• pp.662-665
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• 2004

In this paper, based on shaking table test results on a seismically isolated bridge model, an inelastic numerical model is refined by using Bouc-Wen model representing the hysteretic behavior of isolators. Seismic responses of isolated bridges are numerically investigated varying with relative stiffness ratios, which is a ratio of the effective stiffness of isolator to the lateral stiffness of bridge pier. From the results, it is found that an adequate range of relative stiffness ratio could be defined for seismic design of isolated bridges without considering the flexibility of piers.

• Steel and Composite Structures
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• v.17 no.5
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• pp.687-704
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• 2014

A great number of moment-resisting steel structures collapsed due to ductile crack initiation at welded beam-column connections, followed by explosive brittle fracture in the Kobe (Hyogoken-Nanbu) earthquake in 1995. A series of experimental and numerical studies on cracking behaviors of beam-column connections in steel bridge piers were carried out by the authors' team. This paper aims to study the effect of post weld treatment on cracking behaviors of the connections during a strong earthquake event. Experiments of three specimens with different weld finishes, i.e., as-welded, R-finish, and burr grinding, were conducted. The experimental results indicate that the instants of ductile crack initiation are greatly delayed for the specimens with R-finish and burr grinding finishes compared with the as-welded one. The strain concentration effect in the connection is also greatly reduced in the specimens with post weld treatment compared with the as-welded one, which was also verified in the tests.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2008.04a
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• pp.104-107
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• 2008

A case study is conducted by between using 3D integrated automatic design software(ABeamDeck, AAbutPier) and using autocad without program to validate the method. As a result, there are many profits introducing the 3D design in the construction, especially, to make up for defect of existing design method. 3D design will enhance the efficiency of construction tasks by supporting a system of sharing and exchanging information throughout all the stages of construction, from design, production and installation to maintenance.

• Journal of the Korean Geotechnical Society
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• v.17 no.3
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• pp.5-13
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• 2001

세립토에서의 세굴깊이의 발달은 일반적으로 조립토에서보다는 아주 천천히 진행된다. 조립토를 위해 개발된 방법을 시간효과와 무관하게 세립토에 적용한다면 세굴깊이가 과대하게 평가된다. SRICOS 방법은 점성토 또는 연암에 설치된 교각의 국부세굴깊이의 변화를 예측하기 위해 개발되었으며, 교량현장에서 채취한 흙에 대한 실험과 SRICOS 프로그램의 수행을 병행함으로써 적용된다. 본 논문에서는 SRICOS 방법을 간단히 설명한 후 프로그램의 세부적인 내용을 기술한다. 또한 이 프로그램을 이용하여 세굴에 미치는 각 매개변수의 영향을 평가하기 위해 실시한 매개변수 해석의 결과가 포함된다.