A Long-term Deflection Calculations Of Partially Prestressed Concrete Grider Bridge With The Effect Of Cyclic Loading

With the rapidly development of transportation and economy, the prestressed concrete girder bridges gain wide application in the road with the advantages of its high stiffness, comfortable, mature technology.It has a considerable proportion in china's highway bridges. However, due to various reasons,prestressed concrete girder bridges have a common phenomenon about excessive midspan sag across the service stage.The structure's design of long-term deflection is much higher than it's calculated result. It will have negative effect on the service performance and structure safety of the bridges which has already become a serious obstacle of this kind of bridges' development. Research and analysis of long-span prestressed concrete bridges about the reasons of downwarping and the method of long-term deflection calculation, proposed the design and construction measures of the prestressed concrete girder downwarping , searching the method of deflected prestressed concrete beam which has became the urgent problem of china's bridge engineering field.This contex based on the situations of prestressed concrete beam's general deflection. Analyzed and summarized the calculate method of traditional partial prestressed concrete girder about long-term deflection.Usually the mobile load is considered as the static load .However in the service stage,bridges also withstand repeated load frequently except the static load. The resistance will decline along with the accumulation of the fatigue damage and cause the degradation or failure of structure function ultimately.The deformation will increase under working load.In order to accurately calculate the deflection in the future considering the discipline about deflection of girder under repeated load.This contex summarize the results that the fatigue test of partial prestressed concrete construction ,working out the calculation model in considering under repeated load about the patial prestressed concrete bridge and for the development_discipline of long-term deflection of actual bridge,finally carry out the forecast and corresponding conclusion which can provide the basis and technical support for the long-term deflection calculations of partially prestressed concrete grider bridge.