Stability Analysis Of Arch-tower Of Cable-stayed Bridge

With the city's economic development and the necessary construction, aesthetic requirements of bridges become more and more important. Some of the more beautiful bridges will be built in the cities, but they are always more complicated or special in the structure. Yanji arch-tower cable-stayed bridge is this kind of bridge.The bridge tower is quite unique that the tower is ellipse arch in the horizontal bridge approaches and is "V" type in the vertical bridge approaches because the two arch towers incline 20°angle to each side.This tower is the first construction in domestic.The stability of this tower is an important example in the construction stage and the operational stage.The model of the tower is simplified and the critical load is got by Successive approximation method in the construction stage analysis. The buckling eigenvalue of each construction stage is got by Calobove method. The analysis results indicate that the arch tower is safe at stability in the construction stage, and the buckling eigenvalue is smaller with the construction evolving. In addition, the effect of wind load to the buckling eigenvalue is analysised in each construction stage. The results show that the effect of wind is little, and it is smaller with the construction evolving, which is 0～2%.In this paper, the stability program is compiled by Matlab based on spatial finite element theory, and it is validated by the program Midas and Ansys. The buckling eigenvalue of each possible load and load combination is caculated by this program and the effect of wind load, the overall temperature and the moving load is analysised in the operational stage. The results reveal that the buckling style is the roll-plane instability primarily, the buckling eigenvalue of each load case meet the code, the effect of wind load and the overall temperature to the buckling eigenvalue is little, the effect of moving load is about 5%.The geometry non-linear buckling analysis of the tower is carried on in the construction stage by the program Midas. The load- displacement curve is obtained in the construction stage and the operational stage. The results indicate that the buckling eigenvalue reduces about 20%～30% because of the effect of the geometry non-linear. Therefore, it is necessary to reckon the effect of the geometry non-linear in when the buckling of the tower is analysis.