A new type of PSC girder bridge is proposed in this study which is well suited for long spans without enlarging depth. Design theories of the proposed girder are proved as well through experiments.
The proposed bridge has three major advantages, which are (1) the tensioning performed step by step which improves efficiency, and (2) tensioning force can be controlled depending on the girder's condition by using the system having ability to adjust the tensioning force, and (3) the efficiency of tensioning and the safety on construction are enhanced by applying the concrete slab compounded with PC panel.
This study consists of two different types of experiment. The first one is an experiment on the girder which is able to control tension force, and another one is an experiment on the concrete slab compounded with PC panel.
Two different types of full scale girders were casted for this study. They are classified based on the type of slab, i.e., cast in place deck and stay in place precast panel with cast in place topping. The girders were made and a tension control test was performed for verifying the system which can adjust tensioning force followed by a static load test in order to check the cracking load and ultimate strength.
In order to verify the composite behavior of the slabs, two variables, such as scratching of slabs and shear key, were set up. This experiment was performed for the horizontal shear test and fatigue test to check the behavior of the slab when it acts compositely.
From the results of girder test, it was verified that the system is able to control the tensioning force well enough. A cracking load which was estimated through static load test is obtained as 2.5 times more than that of service load which clearly means that it is safe from crack point of view. Also while cracking occurs, deflection was found to be under the range of allowable deflection which showed the stiffness of girder is sufficient enough. Moreover, since the estimated values obtained from test and the theoretically analysis values are good agreement, it can be assure that the experiments were performed well without any problems and the design theory of the proposed girder was also reasonable.
PC panel and concrete behave as structural member as the shear force obtained through frictional force is sufficient enough. In addition, the proposed slab keeps its required strength even after fatigue test up to the limit of service load.
본 논문에서는 형고를 높이지 않고서도 장경간에 적용가능한 새로운 형식의 PSC 거더교를 제안하였으며 실험을 통하여 설계 개념을 검증하였다.
제안된 거더교는 세가지의 이점을 가진다. 우선 시공단계에 따라 단계적으로 긴장력을 도입함으로서 효율성을 높였으며, 또한 긴장력 조절이 가능한 시스템을 적용하여 거더의 상태에따라 긴장력을 조절할 수 있도록 하였다. 마지막으로 PC 패널을 합성한 바닥판을 적용하여 효율적인 긴장뿐만 아니라 시공상의 안전성을 확보하였다.
본 논문은 긴장력 조절이 가능한 PSC 거더에 관한 실험과 PC 패널을 적용한 합성 바닥판에 대한 실험으로 구성되어 있다.
거더에 관한 실험을 위해 두 개의 실물 크기의 실험체가 제작되었으며 각각의 실험체는 바닥판의 종류에 따라 일체 현장타설 바닥판을 사용한 경우와 PC 패널을 적용한 경우로 구분된다. 거더의 제작 이후 긴장력 조절 실험과 정재하 실험이 수행되었다.
바닥판의 실험에서는 스크래칭과 전단키의 유무를 변수로 하는 실험체가 제작되었으며 수평전단 실험과 피로 실험을 통하여 합성 바닥판의 일체 거동 여부를 평가하였다. 거더의 실험을 통해 단계적인 긴장과 긴장력 조절이 가능한 시스템의 효과를 검증하였고, 사용상태에서 휨균열에 대해 안전하고 충분한 내하력을 가짐을 확인하였다. 또한 사용하중과 균열하중이 가해졌을 때 모두 허용 처짐을 만족하였으며 실험 결과는 이론적인 해석값과 유사하게 나타났다.
바닥판의 실험의 경우 본 실험에서 적용된 합성 바닥판은 현장타설 바닥판과 같은 일체성을 가지며, 사용 휨 하중에 대해 충분한 피로 성능 확보함을 확인 할 수 있었다.
