High Pier Span Prestressed Concrete Continuous Rigid Frame Carrying Capacity Analysis

Now, many long-span PC continous rigid frame bridges with tall piers have been built in our country, especially in northwest part. As more and more such bridges are built, more attention is paid to its safety during builting, ultimate bearing capacity, endurance capacity and so on. It is significant and valuable to study ultimate bearing capacity of these bridges for ensuring the safety of these bridges in service and improving the technique of design, construction and so on.As an important part of communication scientific research item of Shaanxi- 'Field test and bearing capacity judging method research for long-span PC continous rigid frame bridges with tall piers' (04-14K). Based on Xushuihe bridge in Shaanxi YU-YAN expressway, space emulate finite element model is established with shell and link elements in Ansys. This model includes concrete box-beam built in step, hollow thin piers, presressed bars and bars of piers. And all-time space emulation analysis with double nonlinear was realized by element 'live and dead 'capacity in Ansys.The ultimate bearing capacity and normal bearing capacity are analyzed with double nonlinear. The rule of internal force and stress distributing of these bridges is studied. The result from linear elastic in-plane model with bridge special analytical program, result made by space double nonlinear in Ansys and result made by field test are compared. Then the applicability and limitation for the design and calculation of box beam is studied. The effects of some factors on ultimate bearing capacity of long-span PC bridge with tall piers are studied, such as different loads, different temperature change and difference between new and old criterions. The influence of temperature change is greater in these factors. The paper also offers the destruction process and mode of the structure under different loads.This paper offers a finite element analysis method, which is helpful to understand the internal force distributing, the destruction process and mode and the different factors influencing the ultimate bearing capacity of these bridges. It also gives some useful conclusion to the judge of bearing capacity, over loading capacity and safety.