Research On The Long-term Deflection Control Measures Of Long-span PC Continuous Rigid-frame Bridge

At present, the main problem of the domestic long-span prestressed concrete girder bridge is that inter-and long-term deflection is too big and the crack of the box girder, and it is meaningful to study how to control inter-and long-term deflection of long-span prestressed girder bridge.In this paper, firstly the author will take the project of the Hanyuan DA Shu River Bridge as the background, use finite element simulation software for analogy calculation, and compare effects of the sizes of the prestressed top cables, web prestressed cables, prestressed bottom cables, vertical prestressing tendon and each box on the midspan deflection of the large inter-PC continuous rigid frame bridge, as well as prestressed stress of full-bridge.Secondly, aiming at the current situation that the loss estimation of long-span continuous rigid frame bridge PC prestressed cables is in serious shortage, the author will discuss the numerical value of the parameters in the friction loss formula, and analyze the influence caused by the hardening accelerator on prestressed concrete compression loss of flexibility and prestressed concrete shrinkage and creep loss.Thirdly, the web crack phenomena on the continuous rigid frame bridge caused by the vertical prestress losses, the author will recommend to use web inclined prestressed cables in place of vertical prestress cables, to prevent the web cracks, and maintain rigidity box to control the late deflection of the main beam.Finally, aiming at the present bottom tension crack situation of continuous rigid frame bridge, the author will propose the linear layout of bottom beams, take the project of the Hanyuan DA Shu River Bridge as the background and use finite element simulation software for analogy calculation. when the prestressed concrete structures are arranged in a straight line, the deflection of midspan,the max bending moment and the max principal tensile stress are improved.