An experimental study on the structural behavior of connection types between approach slab and integral abutment has been done for three typical bar connections. Typical hinge style reinforcing bar detail for its connection is preferred in order to accommodate rotation of the approach slab among engineers. However, the straight horizontal bars can be used as connection detail accomodate structural capacity. Total six specimens with three types of rebar detail are tested for direct tensile and bending load. The characteristic structural behaviors are carefully monitored and all the strain gauge data obtained are analyzed. It is shown that the structural performance of all the specimens well exceed its design allowance. Several design suggestions are given based on careful reviews on the experiment.

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.

2종류의 질화규소에 대하여 Ring형시험편을 이용하여 접촉피로시험을 하였다. 질화규소는 금속재료에서와 같은 형태의 피로현상을 나타냈고, 파면해석 및 관찰결과 접촉피로에 있어서 균열의 발생은 고탄소크롬강의 경우와 같이 표면하의 반복전단응력에 의한 것으로 밝혀졌다. 그리고 시험펴 파단면에서 표면하의 Heltz전단응력의 변동이 최대로 되는 깊이의 위치에 다수의 균열이 관찰되었다.

본 연구에서는 접초피로에 있어서 균열의 발생, 진전 등의 관찰을 위해, 균열의 발생, 진전 등이 2차원적으로 되어 시험편측면에서 관찰이 가능한 평판 ring형 시험편을 이용하여 반복수 증대에 따른 균열의 발생, 진전과정을 조사하였다. 그 결과 pitting, flaking형 파손의 초기손상은 접촉면하의 내부에 생기는 접촉면에 평행방향의 균열에 의해 일어나며, 이 균열은 그 방향 밀 파면형태에 의해 접촉응력이 접촉면에 평행방향의 전단응력성분에 의한 모드 ll 피로진전과의 차는 중첩부하된 압축응력의 유무라고 생각되며, 이 가저에 근거로 하여 재료고유의 모드 ll 피로균열진전특성을 구할 수 있는 장치를 개발하였다. 이 장치를 이용하여 알루미륨합금 및 공구강에 대한 da/dN-δk ll 관계의 시험결과를 얻었다.

본 연구는 가스압소결 질화규소의 혼합모드에 있어서 파괴거동을 실온 및 1000˚C에서 조사하였다. 실험은 누프압흔을 도입한 시험편을 사용하여 소둔처리에 의해 잔류응력을 제거하고, 4점굽힘법을 이용하였다. 실험결과, 종래 제창되고 있는 파괴기준과 일치하지 않고, 그래서 새롭게 4차관수의 근사식을 제안하였다.

This paper presents a rope modeling and verification for the robotic platform of the wall cleaning robot (ROPE RIDE). ROPE RIDE has the characteristics of climbing up and down using a rope fixed on the roof like traditional workers. In order to perform a stable operation with a wall cleaning robot, it is necessary to estimate the position of the robot in a vertical direction. However, due to the high coefficient of extension and nonlinearity of the climbing rope, it is difficult to predict the behavior of the rope. Thus, in this paper, the mathematical modeling of the rope was carried out through the preliminary experiment. Extensive experiments using different types of rope were used to determine the parameters of the constitutive equation of climbing ropes. The validity of the determined parameters of various ropes was verified through the experiment results.

A numerical case study of stub type abutment consist of square wall pile and retaining wall has been done for its possible application. The FEM analysis using 3 dimensional elements is performed for defining its characteristic behaviors with respect to its construction sequence. The results indicate that the pre-construction of reinforced wall before installation of the square wall pile is more effective in the view point of the displacement and stress.

강․콘크리트 합성구조에서 강재와 콘크리트 사이의 경계면에 효과적인 응력전달과 합성거동을 유도하기 위하여 스터드, 채널, 유공강판 등이 사용된다. 가장 광범위하게 사용하는 전단연결재는 스터드 형식이고, 최근에 들어서는 강판에 구멍을 뚫은 유공강판전단연결재인 Perfobond가 주목을 받고 있다. 본 연구는 강․콘크리트 합성교량에 적용하기 위한 Perfobond형 전단연결재의 연성능력과 전단성능을 향상시킬 목적으로 횡방향 전단구속철근을 배치하고, Push-out 실험을 수행하여 전단내력을 비교하였다. 실험결과, 유공강판 전단연결재에 전단구속철근, 횡방향 관통철근, 단부 지압판 등을 설치함에 따른 수평 저항성능이나 다웰효과 등에 의해 전단내력이 상승하였으며, 또한 최대내력 이후 변형능력이 유지되면서 연성거동 특성을 보였다.