Prestressed concrete (PSC) is a method in which prestressed tendon is placed inside and/or outside the reinforced concrete member and the compressive force applied to the concrete in advance to enhance the engineering properties of concrete member which is weak under tension. In this paper we suggested the precast PSC girder assembled with segments of portable size and weight at the factory. The segments of precast PSC girder will be delivered and assembled as a unit of PSC girder at the site. Consequently, we suggested new-type of precast segmented PSC girder with different shapes of segment cross-section (i.e., I-shape, Box-shape). To mitigate the problems associated with the field splice between the segments of precast PSC girder anchor system is attached near the neutral axis of the girder and relatively uniform compression throughout the girder cross-section is applied. Prior to the experimental investigation, analytical investigation on the structural behavior of precast PSC girder was performed and the serviceability (deflection) and safety (strength) of the girder were confirmed. In addition, 4-point bending test on the girder was conducted to investigate the structural performance under bending. From the experimental investigation, it was found that the precast PSC girder spliced with 3 and 5 segments has sufficient in serviceability and safety conditions and it was also observed that the point where the segments spliced has no defects and the girder behaves as a unit.

본 연구에서는 변장비 1:5.5의 PSC 박스거더단면을 대상으로 적용사례가 많은 페어링 3종류와 1종류의 플랩에 의한 제진효과를 풍동실험을 통하여 고찰하였다. 직각삼각형 페어링을 기본단면에 부착한 경우(A1, A2) (+)영각 에서 비틀림 와류진동응답이 증가하였고 비틀림 플러터에 대하여 등변 직각삼각형 페어링(A1)은 두드려진 개선효과는 없었으나, 부등변 직각삼각형(A2)의 경우는 한계풍속이 증가하였다. 정삼각형 페어링의 경우는 플러터 한계풍속이 감소하고 와류진동응답이 증가하는 역효과가 나타났으며, 기본단면의 내풍대책으로서는 적합하지 않은 것으로 사료된다. 난간 상부에 플랩을 설치한 경우 모든 영각범위에서 와류진동진폭이 감소하였으며 비틀림 플러터의 한계풍속도 증가하는 것으로부터 한정진동 뿐만 아니라 발산진동에 대해서도 매우 효과적인 제진대책이라 판단된다.

Although steel has high strength compare to concrete as structural material, usage of it decrease because of its cost. Steel, however, is not only easy to manufacture but also convenient for manufacture. Using these advantages of steel, it is possible to reduce the cost of construction, The steel bridge can be constructed by modular system. In this study, structural analysis is performed to estimate section strength of steel box girder which is made by the method of fold.