• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2004년도 가을 학술발표회 논문집
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• pp.163-170
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• 2004

The main objective of this research is to determine the optimal sections of infrastructure (the pier and foundation) for orthotropic steel decks which is a part of prefabricated passenger car overpasses. Since the bridge to be designed allows only passenger cars, design loads are determined according to this condition. The total volume of the infrastructure is formulated as the objective function and the design constraints are based on the 'Korean Bridge Design Code' and 'Design Manual of Steel Framed Pier'. The programs used in this research are MATLAB 6.5 and MIDAS CIVIL.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1998년도 가을 학술발표회 논문집
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• pp.216-222
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• 1998

Effects of translational and rotational motions of the foundation on the dynamic behaviors of a bridge under seismic excitations are examined by utilizing a simplified 3 degree-of-freedom of system. To consider the nonlinear characteristics of the RC pier, a hysteresis model is adapted, which can simulate the inelastic motion of the pier with the stiffness degradation. From results, the portion of the total displacement due to rotational motion of the foundation becomes larger as applied seismic excitation increases.

• 한국산학기술학회논문지
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• 제21권1호
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• pp.163-168
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• 2020

우리나라는 1960년대 산업화 이후 하천 및 해상에 교량을 건설 하는 등 교통 기반시설을 활발하게 확충하였다. 교량 건설로 인하여 안정성 검토에 대한 많은 연구가 진행되고, 안정성 확보 기술이 개발되었다. 그러나 교량 상부를 중점으로 하여 기술이 개발됨에 따라 교량 하부에 대한 안정성 확보 기술 및 검사는 제한적인 실정이다. 특히 교각에서 발생하는 세굴현상은 하상에 침식 및 교량의 붕괴를 초래하기에 이에 대한 대책 수립 및 예방이 필요하다. 본 연구에서는 세굴현상에 따른 교량 피해를 예방하기 위한 기초 연구로서 교각 세굴심 산정 경험식을 개발하였다. 기존의 연구에서 진행된 수리모형실험 자료를 바탕으로 다중 선형 회귀분석을 실시하였으며, 이를 통하여 경험식을 개발하였다. 그 결과, 개발된 경험식은 0.91의 R²을 보이고 있으며, 개발된 식을 검증하기 위하여 개발에 활용되지 않은 모형실험 자료에 적용하였다. 23개 경우에 대하여 진행된 기존 모형실험의 결과와 개발된 식을 활용하여 산정된 교각 세굴심을 비교하였을 때, 약 70%인 16개 경우에서 20% 이하의 오차율 확인하였다. 이를 통하여 본 연구에서 개발된 경험식은 교각 세굴심 산정에 있어 적합한 적용성을 보인다고 판단할 수 있다. 향후 추가적인 연구를 통하여 보다 정확한 교각 세굴심 산정 경험식을 개발 할 수 있을 것이며, 세굴에 의한 교량 피해를 저감할 수 있을 것으로 기대된다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2010년도 춘계 학술대회 제22권1호
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• pp.131-132
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• 2010

최근 신설된 교량의 경우에는 개정판 도로교 설계기준에 의해 내진설계를 수행하여 시공되고 있으나, 내진설계규정이 적용되기 이전에 시공되어 사용중인 철근콘크리트 교각의 경우에는 지진에 취약할 수 있다. 반복 횡하중을 이용한 실내시험을 통해 교각 시험체를 니켈-크롬 합금강바 보강 전후 및 보강형태에 따른 부재의 거동변화를 측정분석 하였다.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 2001년도 추계 학술발표회 논문집 Proceedings of EESK Conference-Fall 2001
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• pp.131-138
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• 2001

The purpose of this study is to investigate size effect on inelastic behavior of reinf bridge piers subjected to cyclic load. A computer program, named RCAHEST(Reinforced Co Analysis in Higher Evaluation System Technologr), for the analysis of reinforced concret was used. Material nonlinearity is taken into account by comprising tensile, compressiv models of cracked concrete and a model of reinforcing steel The smeared crack app incorporated. In boundary plane at which each member with different thickness is conne discontinuous deformation due to the abrupt change in their stiffness can be taken into introducing interface element. The effect of number of load reversals with the same d amplitude has been also taken into account to model the reinforcing steel. To determine th on bridge pier inelastic behavior, a 1/4-scale replicate model was also loaded for compar full-scale bridge pier behavior.

• International Journal of Safety
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• 제10권1호
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• pp.22-31
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• 2011

Seismic response control method of the bridge structures with semi-active control device, i.e., magneto-rheological (MR) damper, is studied in this paper. Design of various kinds of clipped optimal controller and fuzzy controller are suggested as a semi-active control algorithm. For determining the control force of MR damper, clipped optimal control method adopts bi-state approach, but the fuzzy control method continuously quantifies input currents through fuzzy inference mechanism to finely modulate the damper force. To investigate the performances of the suggested control techniques, numerical simulations of a multi-span continuous bridge system subjected to various earthquakes are performed, and their performances are compared with each other. From the comparison of results, it is shown that the fuzzy control system can provide well-balanced control force between girder and pier in the view point of structural safety and stability and be quite effective in reducing both girder and pier displacements over the existing control method.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 2003년도 춘계 학술발표회논문집
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• pp.377-384
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• 2003

Recently, there are much concerns about new and innovative transverse materials which could be used instead of conventional transverse steel in reinforced concrete bridge piers. FRP materials could be substituted for conventional transverse steel because of their sufficient strength, light weight, easy fabrication, and useful applicability to any shapes of pier sections, such as rectangular or circular sections. The objective of this research is to evaluate the seismic performance of reinforced concrete bridge pier specimens with FRP transverse reinforcement by means of the Quasi-Static test. In the first task, test columns were made using FRP rope, but these specimens appeared to fail at low displacement ductility levels due to insufficient confinement of strand extension itself. Therefore, the second task was to evaluate the seismic performance of test specimens transversely confined with FRP band. Although FRP banded specimens showed lower seismic performance than the specimen with spiral reinforcing steel, it satisfied with the response modification factor, 3, required for the single column of Korea bridge roadway design code. It was concluded that FRP band could be efficiently substituted for conventional reinforcing steel.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 2003년도 춘계 학술발표회논문집
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• pp.409-414
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• 2003

A multi-span bridge model that is fixed in longitudinal direction at a single pier can be very vulnerable to the earthquake ground motion in longitudinal direction. If the seismic load exceeds the capacity of the pier, it can be severely damaged. However, such incident can be prevented if piers of movable support share the seismic load as setting up seismic load transmitting device. This study is performed to investigate seismic performance of continuous bridge model with seismic load transmitting devices which is proposed newly. It is found that continuous bridge model system with device is more effective about displacement control and seismic performance.

• Structural Engineering and Mechanics
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• 제81권2호
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• pp.117-129
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• 2022

This research evaluated the different types of deck to pier connections effects (one or two elastomeric bearing lines and rigid) on a concrete bridges. Three-dimensional bridge models behavior with different deck to pier connections and different distances of two bearing lines were studied under the service load. Also, the detailed connection system with two elastomeric bearing lines was modeled to evaluate the effect of changing distance between two-lines. Results indicated that the proper location of elastomeric bearings has a major impact on the transferring forces to the substructure. Double elastomeric bearing lines have a behavior between one line and rigid connections. Transferring bending moment to the substructure in two-lines is more than the corresponding value of the one line. Moreover, an increase in the distance of two-lines lead to a significant increase in the rotational stiffness of the connection, and an analytical solution was investigated for their relation. In fact, the semi-rigidity effect of this connection and its change due to the distance of bearings should be considered in the design process.

• 지구물리와물리탐사
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• 제7권1호
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• pp.80-87
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• 2004

During excavation work for the construction of a highway bridge in a limestone area in Korea, several cavities were found, and construction work was stopped temporarily. Cavities under the bridge piers might seriously threaten the safety of the planned bridge, because they could lead to excessive subsidence and differential settlement of the pier foundations. In order to establish a method for reinforcement of the pier foundations, borehole radar reflection and tomography surveys were carried out, to locate cavities under the planned pier locations and to determine their sizes where they exist. Since travel time data from the crosshole radar survey showed anisotropy, we applied an anisotropic tomography inversion algorithm assuming heterogeneous elliptic anisotropy, in order to reconstruct three kinds of tomograms: tomograms of maximum and minimum velocities, and of the direction of the symmetry axis. The distribution of maximum velocity matched core logging results better than that of the minimum velocity. The degree of anisotropy, defined by the normalized difference between maximum and minimum velocities, was helpful in deciding whether an anomalous zone in a tomogram was a cavity or not. By careful examination of borehole radar reflection and tomography images, the spatial distributions of cavities were delineated, and most of them were interpreted as being filled with clay and/or water. All the interpretation results implied that two faults imaged clearly by a DC resistivity survey were among the most important factors controlling the groundwater movement in the survey area, and therefore were closely related to the development of cavities. The method of reinforcement of the pier foundations was based on the interpretation results, and the results were confirmed when construction work was resumed.