Analysis Of Stiffness And Cracking Of High Pier Continuous Rigid Frame Bridge

In view of the continuous rigid frame bridge has the problem of cracking with the growth of operating time, with the cracks developing and growing, the stiffness of the continuous rigid frame bridge would have decreased which would promote the downwarping of main girder. And downwarping would promote the craking. Currently, the study of the bridge structure and the impaction of cracking and stiffness is seldom. Analyzing the cracking and stiffness of continuous rigid frame bridge has been an urgent problem to solve.This paper will base on the finite element program’s analysis capabilities and combine real bridge cracking investigation to analysis the cracking and stiffness of multi-span continuous rigid frame bridge by the simulation calculation methods.First of all, this paper mainly introduce the analysis the basic theory about cracking and deflection of multi-span continuous rigid frame bridge.Introduction of box girder structure space stress state and the box girder stress analysis method; Then introduce the basic theory of box girder crack, including the mechanism of cracks, classification and the factors influencing of the cracking of box girder of prestressed concrete box girder cracks; State the downwarping and expounds the structure principle, related calculation formula and deflection causes; For subsequent sensitivity analysis provides the foundation theoretical study. In follow-up study,this paper would analyze its effects on cracking and stiffnessin deflection interaction relations when the girder deflection and stress is different.Secondly, relying on the actual project of Hongling Bridge, and make a brief project description the five-span continuous rigid frame bridge. Making an analysis of space beam element simulation by Midas/Civil. Using Ansys No.0blocks’complex parts to make a local force entity analysis; Hongling Bridge is a high viaduct pier continuous rigid frame bridge, pier beam stiffness ratio determined the internal force distribution and continuous rigid frame bridge is statically indeterminate structure, additional internal forces due to temperature in a large proportion of the design, so this paper make an analysis of the prestressed loss, pier stiffness and temperature gradient under the main beam cracking and make a conclusion about it.Thirdly, setting the statistical parameters to calculate the three cracks of Hongling viaduct and analysis current situation and future development of cracks crack law.Using inclined plane frame model to simulate cracks and refer to the cracks reference statistics to analysis the cracking of multi-span prestressed concrete rigid frame bridge in different locations and crack-related parameters on the main beam stiffness; Using three cracked plane frame model state to make a calculations and get an conclusion that stiffness reduces effect the main beam cracking and deflection.Finally, in order to verify the actual load carrying capacity and stiffness of Hongling under viaduct cracking state, this paper makes a load test of the bridge static. Detailing the bridge static load test pilot program at great length, and using space beam element model to calculate the control section theoretical value in the design of the stress and deflection. To data processing the control section of the measured strain and deflection in each test condition values. Based on theoretical values to viaduct carrying capacity of Hongling Bridge.