Analysis For Ultimate Bearing Capacity Of Space-twisting Cable Hybrid Girder Cable-stayed Bridge

With the development of our national economy and the people's demand of urban landscape, in recent years space cable twist beams back cable-stayed bridge has appeared in some city. Space cable twist beams can completely meet the requirement of the public use as conventional cable-stayed bridge, and it is also beautifully-shaped and suitable for the urban landmark buildings. Therefore, this kind of bridge has received great emphasis and it has been put into practical use in large-scale projects. However, both at home and abroad, there is few analysis of the nonlinear effects in loading and main characteristics of instability of space cable twist back cable-stayed bridge, and the reference documents for the ultimate bearing capacity calculation are also few, so there is still much room for further study.Based on the existing literatures access for cable-stayed bridge and the analysis methods of ultimate bearing capacity, using the classical geometry nonlinear theory and analysis software ANSYS, the author set up the model. According to the bridge main uniformly in the main function, the most unfavorable loading function across the maximal displacement and top loading effects of four of space, twisted back cable geometry nonlinear cable-stayed bridge beams and structural stability is analyzed, and then compare the safety factor of the cable-stayed bridge with prescribed minimum stable safety coefficient. At the same time, according to the comparison of plastic hinge legal theory, structure load-bearing capacity is calculated.It is found that space twisted back structure of the geometrical nonlinearity influence are little. The tower is the first to lose stability in structure's instability under different conditions; the instability under unbalance loading in the first-order stability is obviously less than that in the under mid-loading, and structure is easily lose stability in the condition of unbalanced loading instability. Structural safety coefficient is greater than safety coefficient based on flexible theory in the Design Specifications of Highway Cable Stayed Bridge (on Trial). The global stability of the engineering is greater than the standard stipulated in the whole stability of the cable-stayed bridge. Considering the influence of vertical stay-cables, plastic hinge method of calculating coefficient of load is little; and the minimum of load coefficient is the top loading of tower effects, which means this working condition is the most unfavorable conditions of the ultimate bearing capacity.