PURPOSES : The bridge section of the expressway has a worse driving environment than the general section. However, traffic safety countermeasures are focused only on the bridge section. Traffic safety countermeasures on the section before entry to the bridge and the section after exit from the bridge are applied only when the bridge has a long-span section. Accordingly, this study will verify the necessity of extending the application of traffic safety countermeasures to areas that are affected by the bridge. METHODS: This study determines the areas that are affected by the bridge as well as the areas that are affected by locations with frequent traffic accidents and suggests the risk factors by affected areas through canonical discriminant analysis. For the analysis, traffic accident data for 3 years, which occurred on bridge sections in six major expressway lines, were used. RESULTS: The numbers of traffic accidents were 469 before the bridge, 281 on the bridge, and 468 after the bridge. The variables that have impact on the seriousness of accidents are as follows: speeding, excess manipulation of the steering wheel, and failure to secure safety distance for accidents that occurred before the bridge section; speeding, excess manipulation of the steering wheel, and dozing off for accidents that occurred on the bridge; and speeding and failure to secure safety distance for accidents that occurred after the bridge section. CONCLUSIONS : Areas affected by the bridge show higher accident rates than the bridge section; therefore, imposing traffic safety countermeasures on the integrated section of the bridge and the affected areas is required. It is believed that the results suggested in this study could be effectively used in the prevention of traffic accidents by imposing custom-made safety countermeasures for each section.

ILM 교량은 압출되는 동안 상부의 단면이 지간의 중앙부와 지점부를 모두 통과한다. 따라서 발생되는 최대 정모멘트 및 최대 부모멘트를 효과적으로 제어하기 위해서 압출추진코를 이용한다. 이 연구에서는 압출중 상부구조물에 발생하는 휨모멘트를 계산할 수 있는 다이아프램이 고려된 단순 해석식을 개발하였다. 또한 다이아프램이 고려된 압출추진코의 최적설계조건에 관하여 분석하였다. 단순 해석식을 MIDAS Civil과 비교한 결과 대부분의 경우 0.5%이하의 오차를 가지는 정확성을 확인하였다. 다이아프램의 영향을 고려했을 경우와 고려하지 않았을 경우 사례교량에서 최대 13%의 휨모멘트 차이를 보였다. 또한, 단순 해석식에 적용시킬 등가 등단면의 단위중량 및 평균강성값을 결정할 수 있는 기준을 제시하였다. 이 연구에서는 ILM 교량의 압출중 역학특성으로 인하여 부모멘트 최소화 조건만을 사용하는 것이 압출추진코 최적설계를 위한 효과적인 방법으로 판단하였다.

이 연구에서는 물량저감 철근상세를 갖는 중공 철근콘크리트 교각 시스템의 전용 설계프로그램과 소성설계 적용 결과를 제시하였다. 개발된 물량저감 철근상세는 경제성과 합리성을 갖으며 공사기간의 단축을 가져올 수 있다. 물량저감 중공 철근콘크리트 교각의 적용을 통해 경제성 평가를 수행하였다. 평가 결과 개발상세가 기존상세에 비해 구조적 합리성, 시공성, 그리고 경제성 등이 우수함을 확인하였다.

The purpose of this study is to investigate the seismic performance of hollow RC bridge columns with reinforcement details for material quantity reduction. The proposed reinforcement details provide economy, are rational and shorthen the construction periods. The accuracy and objectivity of the assessment process can be enhanced by using a sophisticated nonlinear finite element analysis program. Solution of the equations of motion is obtained by numerical integration using Hilber-Hughes-Taylor (HHT) algorithm. The adopted numerical method gives a realistic prediction of seismic performance throughout the input ground motions for several test specimens investigated. As a result, the proposed reinforcement details for material quantity reduction develop equal performance to that required for existing reinforcement details.

The study tests a theoretical framework for examining the consumer decision-making process with regards to ethically questionable behavior. The results indicate that subjective norms, perceived behavioral control and self-efficacy are significant predictors of consumer intentions to engage in ethically questionable behavior. Attitude was not found to be a significant predictor.

The plastic hinge region of RC pier ensures its nonlinear behavior during strong earthquake events. It is assumed that the piers secure sufficient strength and ductility in order to prevent the collapse of the bridge during strong earthquake. However, the presence of a lap-splice of longitudinal bars in the plastic hinge region may lead to the occurrence of early bond failure in the lap-splice zone and result in significant loss of the seismic performance. The current regulations for seismic performance evaluation limit the ultimate strain and displacement ductility considering the eventual presence of lap-splice, but do not consider the lap-splice length. In this study, seismic performance test and analysis are performed according to the cross-sectional size and the lap-splice length in the case of longitudinal bars with lap-splice located in the plastic hinge region of existing RC bridge columns with circular cross-section. The seismic behavioral characteristics of the piers are also analyzed. Based upon the results, this paper presents a more reasonable seismic performance evaluation method considering the lap-splice length and the cross-sectional size of the column.

This paper examines the pounding problem between adjacent decks subjected to strong earthquakes. The elastomeric bearings in an isolated bridge reduce the stresses on the superstructure and cushion the impact by transferring smaller seismic forces to the substructure. On the other hand, these bearings also allow large horizontal displacement of the superstructure due to seismic forces. Bridges having various supporting soil conditions and different frequency ratios between adjacent decks are investigated by numerical analysis. In the analysis, decision making is conducted whether the collision took place or not and, the magnitude of pounding force and the duration time of collision are obtained and the results are discussed.

장경간 교량의 낮은 감쇠비로 인하여 발생하는 구조물의 진동은 구조물의 안전성 및 사용성에 부정적인 영향을 미친다. 본 연구에서는 시공 중인 교량에 지배적으로 발생하는 연직 방향 진동을 제어하기 위하여 능동형 질량댐퍼(AMD)를 연구하였다. 대상 사장교의 동특성을 조사하기 위하여 모드 해석이 수행되었으며 이를 바탕으로 제어 성능과 설치 공간에 적합한 AMD를 설계하기 위하서 LQR(Linear Quadratic Regulator) 제어 알고리즘을 사용하였다. 성능 검증을 위하여 건설 단계의 대상 구조물과 AMD를 1/10.5의 상사비로 축소시킨 시작품을 설계, 제작하였으며, 시스템 식별을 수행하여 Linear Quadratic Gaussian (LQG) 제어 알고리즘을 적용하였다. 성능 실험 결과 AMD 제어 시에 높은 제어 효과를 구현하였으며, 실험 결과를 수치해석과 비교를 통하여 제어기 설계의 타당성을 확인하였다.

This paper introduces general concepts of jointless bridges and field construction case of semi-integral bridge with psc girder integrating end-diaphragm. The expansion joints need to satisfy thermal and safety conditions of bridges. General bridges with joints have some problems, which are frequently replacement cycle time from mechanical damage or unstable movement, maintenance cost and more. To solve these problems, Integral Abutment Bridges(IAB) have been applied overseas in the 1930s. In Korea, first IAB was constructed in the early 2000s and precast IAB systems was invented and applied lately. Kyungshin overpass bridge in Incheon is the Semi-IAB constructed, the span length is 2@35=70m and the width is 13.9m. The original plan was to use general joint bridge but design field changed with expectations for advanced economic estimation and maintenance. This changed method of B.I.B bridge construction provided not only workability, construction cost but also safety improvement at the same time.

This paper introduces general concepts of Jointless Bridges and field construction case of Semi-Integral Bridge with PSC girder integrating end-diaphragm. The expansion joints need to satisfy thermal and safety conditions of bridges. General bridges with joints have some problems, which are frequently replacement cycle time from mechanical damage or unstable movement, maintenance cost and more. To solve these problems, Integral Abutment Bridges(IAB) have been applied overseas in the 1930s. In Korea, first IAB was constructed in the early 2000s and precast IAB systems was invented and applied lately. Kyungshin overpass bridge in Incheon is the Semi-IAB constructed, the span length is 2@35=70m and the width is 13.9m. The original plan was to use general joint bridge but design field changed with expectations for advanced economic estimation and maintenance. This changed method of B.I.B bridge construction provided not only workability, construction cost but also safety improvement at the same time.

It has been more than twenty years since the application of GFRP bridge decks in construction fields. Recently, a few studies by governments and individual researchers have investigated in-use GFRP bridge decks. Areas of trouble include the problems of cracking, spalling and the de-bonding of the pavement or the wearing surface on GFRP bridge decks, all of which affect the long-term durability and serviceability of these new construction materials. Related to these problems, reflective cracks on asphalt pavement are directly related to pultruded GFRP bridge decks. This study investigates the behavior of an adhesive joint under weak-axis bending by tests and FE analyses to identify the causes of pavement cracks in in-use pultruded GFRP bridge decks. In detail, the flexural stiffness and the load-carrying capacities in strong and weak axes are measured during bending tests on pultruded GFRP decks. Next, tensile local failures of an epoxy adhesive due to the concentration of deformations at adhesive joints are identified via a weak-axis bending test. Finally, the tensile failure of an epoxy adhesive due to the local concentration of deformation at an adhesive joint under weak-axis bending is verified through a finite element analysis.

In recent days composite bridge decks are increasingly used to new and rehabilitated bridges due to their many advantages such as light weight, high strength, high durability, low maintenance costs and fast installation. To further promote usage of composite bridge decks, the authors have developed decks of new profile having innovative vertical snap-fit connection. Through this development, significant enhancement of constructability and economy are obtained by overcoming the drawbacks of conventional composite decks of tongue-and-groove connection. The paper introduces some research results and notable applications for the developed composite decks of snap-fit connection using for pedestrian bridges. Owing to their considerable advantages of the developed composite decks, increasing number of applications is currently underway in Korea.

This study considers the proper repair techniques by examining the most representative repair cases of the Korean arch bridges and proposes the constructional manual which can apply similar occasions. The cases are Seonamsa Seungseongyo and Songgwangsa Geukrockgyo where this researcher had taken part in the repair works. This Study proposes the maintenance construction manual about the performance degradation drew by performance degradation of the both Korean arch bridges in the maintenance process. First, arch bridge maintenance should be carried out in the dry season, when water is impermeable in the bottom surface of the bridge. Moreover, risk factors of the maintenance should be excluded to secure the water vally flow, the bypass and the temporary bridge. Second, prior to repair, it has to precede ①3D shooting ② formal examination ③structure safety test ④geological and lithic surveys ⑤arch curvature establishment and makeshift frame settlement before transformation ⑥relationship expert comments. Third, if the baduk and the foundation stones are inevitable to replace due to performance degradation on the foundation, it should use the high quality stones and secure greater stress by extending the standard range. The foundation on irregular rock needs to be flattened and underside on the replaced materials require Grengyijil to deliver the equal loads. Fourth, In the process of dismantling the stones of the arched bridge, it could make heavy weathering degree and not reuse the materials. Charge should converge the expert advices to choose the reuseable, the conservate and the alternative materials, and increase the reutilization of the raw materials by preservation and reinforcement treatments. Fifth, the side wall should be repaired by the rubble work technique which is not able to pile compost satiety, so it must use long depth of masonary stones for reinforcement. It is considered to reinforce the stone wall in shore as much as possible and protect the abutment and the side wall on the upstream for the arch bridge maintenance works.