Analysis of PSC Box Girder???s Deformation Caused by Pre-stress Loss Exposed to Fire

Recently years, the bridge fire is take place frequently, so the bridge fire bearing capacity has attracted more and more attention by the global researchers???especially the PSC box bridge. so it???s necessary to do the research of PSC box bridge beam exposed on fire to get the fire-resistant performance. but the fire test cost is too high and it???s difficult to simulate the complicated boundary condition. so we use ANSYS finite element program to calculate the PSC box girder. Classificated the result of the research on various mechanical properties of concrete and prestressed tendon under and after high temperature in domestic and foreign. Comparative analysis, and determine a suitable thermodynamic parameters for prestressed box girder bridge displacement field analysis, which mainly refers to the constitutive relation. Based on the basic principle of thermodynamics, formulated the basic methods and steps of the finite element solution. By using the transient analysis mathods on the box girder span section, a fire temperature field nonlinear analysis have been done, and obtained the fire temperature distribution on box girder section at standard temperature curve. In addition, The influence of the loss of prestressed tendon and the loss of concrete strength on the deformation of the bridge was considered, and the influence proportion between the the loss of prestressed tendon and the loss of concrete strength was analyzed. Using thermal-structure indirect coupling method,make a nonlinear analysis on the prestressed concrete simply supported box beam bridge displacement field at high temperature. And by time of fire, In all these steps, prestressing loss is considered.Maste