Study On Nonlinear Stability Of Concrete-filled Steel Tube Arch Bridge

Because of many advantages such as high carrying capacity, upstanding plasticity and toughness, better economic effect, the concrete filled steel tube bow string arch bridge have been more and more widely used in bridge structure. Howerver, arch bridge transmit the applied loads to axial force mainly, which makes arch bridge uniquely susceptible to bucking failure , especially with the slender arch ribs.Generally stability problem is divided into two sorts. The first one can come down to evaluate eigenvalue problem finally, which is very easy to be calculated; the second one can be called imbalance at extremun that is belong to nonlinear, many of arch is the second one actually. This dissertation analyses the development and the research present status of the stability of the concrete filled steel tube bow string arch bridg. Particularly introduces the capability and model of the mechanics, and base on the basic theory of nonlinear and stability analyses, different parameters , such as the ratio of width and span, the angle of toe-in of the arch rib, the variable cross-section, the ratio of height to span and the arch axis coefficient, are discussed in order to analyse the influence to the stability of arch. In project reasonable parameters can be choosed to improve the stability of the concrete filled steel tube bow string arch.the whole stability of different state and the stability of different steps during the process are analysed according to the ture bridge, using finite element method. The result of the calculation indicates that the eigenvalue bucking analysis induce non-conservative result, Due to the material nonlinear influence, the result of nonlinear buckling analysis is far lower than the result of eigenvalue buckling analysis method.