• Journal of the Earthquake Engineering Society of Korea
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• v.4 no.4
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• pp.111-116
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• 2000

경간사이에 creep-coupler가 설치된 경부 고속철도 교량에 TGV-K 열차의 제동에 의한 교량의 종방향 동적거동을 해석하였다. 교량은 40m 길이의 2경간 연속교이며, 종방향 충격 하중을 인접 경간 혹은 교대로 전달하기 위한 목적으로 인접하고 있는 두 교량 사이의 creep-coupler가 설치되었다. 철도교의 경우에는 레일에 대한 종방향 축력검토가 매우 중요하므로, 이를 지지하고 있는 교량의 하부구조(교각과 기초)의영 향을 고려한 교량의 동적거동해석이 요구된다. 본 연구에서는 TGV-K의 실제 제동하중에 의한 KHSR(Korea high speed railway)에 건설중인 실제교량의 동해석을 하부구조와 동특성치를 고려하여 수행하였다. TGV-K는 객차사이에 대차가 위치하므로 전체 열차의 모델링이 한꺼번에 이루어 져야한다. 동핵석을 위해서 열차의 3차원 수치모델링이 이루어졌다. TGV-K의 제동은 동력차의 전기적인 제동에 의한 회생제동력(regenerative braking force)과 객착의 기계적인 판제동(disk braking)으로 이루어진다. 이러한 제동작용의 고려에 실제 TGV-K의 제동함수가 사용되었다.

• Proceedings of the Korean Institute of Industrial Safety Conference
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• 2000.06a
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• pp.223-228
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• 2000

지진격리교량은 강진지역의 지반운동과 구조물의 거동에 근거한 내진설계 개념을 바탕으로 설계되었다. 그러나 지반운동의 특성과 구조물의 거동에 있어서 한반도와 같은 중약진 지역과 지각변동운동이 활발한 강진지역은 큰 차이를 보이고 있다. 따라서 중약진 지역의 내진설계에서는 지반운동의 특성이 반영되어야 할 필요가 있으며, 특히, 지진격리교량의 경우에는 교각의 연성 등 중약진 지역의 구조물의 거동특성이 반영되어야 한다. (중략)

• Journal of the Korea institute for structural maintenance and inspection
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• v.26 no.5
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• pp.161-170
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• 2022

The maintenance of bridges installed in rivers is carried out through facility safety inspection and repair & reinforcement procedures according to the results. Many studies have been so far conducted on the safety check of the bridge upperstructure because of the ease of access. However as it is impossible to directly investigate whether the pier foundation installed in the river has been scoured. Management of underwater foundations has remained based on theory. In this study, the scour of the bridge foundation installed in such a river was realized in 3D form by using an echo sounder and VRS. This made it possible to predict the scour pattern through comparison and analysis with the ground height of the riverbed at the time of the bridge installation. Based on these results, if the pier foundation is used as an initial data to determine whether or not local scour is present and to predict long-term scouring, bridge collapse due to foundation scour can be prevented.

• Journal of Korean Society of Steel Construction
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• v.21 no.4
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• pp.343-350
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• 2009

In the present study, a new seismic retrofitting method that employs both a stainless steel wire mesh and a permeable polymer concrete mortar was proposed for reinforced concrete bridge piers with nonseismic design details. For this purpose, a total of six nonseismically designed bridge piers were tested under lateral load reversals. The test results reveal that nonseismically designed piers with lap splices need to be retrofitted to resist earthquake induced forces. In addition, it was proven that the proposed retrofitting method can be useful in improving the strength, stiffness, and energy dissipation capacities of bridge piers designed nonseismically. It is thus expected that the proposed method may provide an improved ductility capacity without sudden softening of strength for bridge piers excursing inelastic displacement range.

• Journal of the Korean Society for Railway
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• v.13 no.4
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• pp.425-430
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• 2010

This paper investigates the seismic behavior of a prefabricated composite column which is made by onsite connection of precast composite column segments to accelerate bridge construction. Quasi-static cyclic loading tests were performed on three prefabricated composite columns with different connection details to find their seismic capacity. Test results show that the onsite connections remains in elastic range and no slip is observed as designed in spite of plastic hinge formation at the column. The test results also indicate that the prefabricated composite column has better overall seismic capacity compared to a conventional reinforced concrete column with seismic details.

• Journal of Wetlands Research
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• v.22 no.1
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• pp.31-38
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• 2020

Weirs are to secure amount water of streams and drop structures are to enhance stabilization of stream bed and bridges are to connect isolated region, which are called stream crossing structures. In the stream design criteria, directions for minimum size of structures are suggested to secure stability of stream crossing structures. However the sizes of almost all existing weirs and drop structures are not satisfied with the stream design criteria and only 22 percent of the peirs of bridges are satisfied. To enhance hydraulic stability of existing weirs and drop structures, it is required that the ratio of bed protection to apron should be above 3.3. According to factual survey of structures in the sample streams, it has been shown that the longitudinal slope of rapid works with 1:20 is the most reasonable to design velocity if existing weirs and drop structures are rehabilitated into rapid works. It has been known that violating freeboard and span length of piers should make existing bridges reconstructed or removed. However, comprehensive review including deterioration level of bridges, special regulation for span length, etc. should be considered to determine rehabilitation plan of bridges. In this study, a procedure has been suggested to improve hydraulic stability of weirs, drop structures and piers of bridges. Sound environment of stream and reduction of natural disaster could be achieved by improving stability of cross structures, which could be obtained by governmental budget and active stream management including observance of design criteria.

• Journal of the Korea institute for structural maintenance and inspection
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• v.22 no.1
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• pp.147-157
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• 2018

The basis of capacity design has been explicitly or implicitly regulated in most bridge design specifications. It is to guarantee ductile failure of entire bridge system by preventing brittle failure of pier members and any other structural members until the columns provides fully enough plastic rotation capacity. Brittle shear is regarded as a mode of failure that should be avoided in reinforced concrete bridge pier design. To provide ductility behavior of column, the one of important factors is that flexural hinge of column must be detailed to ensure adequate and dependable shear strength and deformation capacity. Eight small scale circular reinforced concrete columns were tested under cyclic lateral load with 4.5 aspect ratio. The test variables are longitudinal steel ratio, transverse steel ratio, and axial load ratio. Eight flexurally dominated columns were tested. In all specimens, initial flexural-shear cracks occurred at 1.5% drift ratio. The multiple flexural-shear crack width and length gradually increased until the final stage. The angles of the major inclined cracks measured from the vertical column axis ranged between 42 and 48 degrees. In particular, this study focused on assessing transverse reinforcement contribution to the column shear strength. Transverse reinforcement contribution measured during test. Each three components of transverse reinforcement contribution, axial force contribution and concrete contribution were investigated and compared. It was assessed that the concrete stresses of all specimen were larger than stress limit of Korea Bridge Design Specifications.

• Journal of the Earthquake Engineering Society of Korea
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• v.10 no.4 s.50
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• pp.85-94
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• 2006

In the design of bridge piers in seismic area, the ductility requirement is the most important factor. In order to enhance the seismic performance of RC columns, it is necessary to make the ductility of columns larger by covering RC columns with steel tubes or confining RC columns by arranging transverse reinforcements such as hoop ties closely. Using core steel composite columns is useful as one of the reinforcing RC columns. In this paper, quasi-static tests on concrete encased composite columns with single core steel or multiple steel elements were performed to investigate the seismic performance of the composite columns. Eight concrete-encased composite specimens were fabricated. The cross-sections of these specimens are composed of concrete-encased H-shaped structural steel columns and a concrete-encased circular tube with partial in-filled concrete. Test parameters were the amount of the transverse reinforcements, type and number of encased steel member. Through the tests, it was evaluated the ductility of SRC composite specimens. It has become clear from the test results that encased steel elements makes the deformation capacity of the columns to be larger. The displacement ductility and lateral strength of specimen with concrete-encased circular tube were indicated the biggest value.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.12 no.3
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• pp.509-518
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• 1999

교량거동의 동적 특성과 인접거덩간의 충돌의 영향을 파악하기 위하여 여러 단순보로 이루어진 교량시스템의 교축방향에 대한 거동을 분석하였다. 충돌은 물론 교각의 비선형, 그리고 기초의 병진 및 회전운동을 고려할 수 있는 단순화된 다자유도시스템을 소개하고 이에 상응하는 운동방정식을 유도하여 교량거동을 예측하는 방법을 개발하였다. 개발된 다자유도시스템은 지진하중을 받는 교량시스템의 거동분석에 대한 적절한 정보를 제공할 수 있는 것을 밝혔다. 충돌의 주 영향은 강진시 인접거더간의 상대변위를 감소시키며, 미진 시에는 상대적으로 증가시킴을 밝혔다. 따라서, 강진이 아닌 지진하중을 받는 교량의 거동분석 시에도 이러한 충돌로 인한 영향에 대하여 각별한 주의가 필요하다는 것을 제안한다.

• Journal of the Earthquake Engineering Society of Korea
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• v.6 no.5
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• pp.45-51
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• 2002

The characteristics of nonlinear seismic behavior and failure mechanism of RC space frame in railroad viaducts have been studied by the numerical analysis in time domain. The structure concerned is modeled in 3 dimensional extent and the RC frame elements consisting of fibers are employed for the columns. The fibers are characterized as RC zone and PC one to distinguish the different energy release after cracking resulted from the bond characteristic between concrete and re-bar. Due to the deviation of the mass center and the stiffness center of the entire structure the complex behavior is shown under seismic actions. The excessive shear force is concentrated on the column beside flexible one relatively, which leads to the failure of bridge concerned.