Research On Fatigue Characteristics Of Prestressed Concrete Continuous Beam Bridge Under The Load Of The Vehicle Loads

With the development of the highway, the prestressed concrete continuous beambridge with its piers less, and other unique advantages of reasonable force favored tobecome the most competitive in different span of bridge and widely used. Prestressedconcrete continuous girder negative moment area reserves have stress, overcome thebridges since the major problem of large weight, the perfect solution to the ultimatebearing capacity of continuous beam bridge almost no doubt that there is often little tobe considered on its fatigue strength, transportation volume surge of prestressedconcrete continuous beam bridge to meet the requirements still exist doubts.This articlefocuses on continuous prestressed concrete beam bridge-the bridge pillars Chongqingas the prototype, using the finite element analysis software ANSYS bridgesuperstructure simulated three-dimensional simulation entities.①Solve the inherent vibration modal analysis of the prestressed continuousbeam bridge after the bridge to determine the stiffness of the weak parts of the site thatis easy to focus on stress fatigue damage dangerous parts．②Generated using MATLAB software vehicle weight lognormal random vehicleload spectrum, the spectrum of random loads acting on the bridge carriageway ofcontinuous beam bridge static analysis and transient (Transient) dynamic analysis．③Analysis based on fatigue S-N curves and prestressed concrete strand oftheory, solving the result after processing by the rain flow counting method to calculatethe fatigue stress dangerous section of the bridges, cycle times and other relevantparameters, according to the linear theory of fatigue damage accumulation, andultimately get dangerous parts material fatigue life and fatigue damage caused. Byanalyzing the results obtained comparing the fatigue parameters: In the movingvehicle load spectrum, the fatigue life of prestressed concrete continuous beam bridgedepends on the fatigue life of concrete materials; vehicle loading bridge tendonscaused power under high stress response is smaller.④Based on actual survey predecessors in Chongqing vehicle load spectrum,random load spectrum with the same traffic loading acting on the same carriagewaybridge, which was surveyed by vehicle load spectrum proportional distribution inprestressed concrete continuous beam bridge fatigue life dangerous parts of the material.By analyzing the results obtained comparing the fatigue parameters: normallydistributed random vehicle load spectrum can be used for checking the prestressingcontinuous concrete bridge fatigue, even more than the proportion of the vehicleaccording to the survey distributed load spectrum load simulation results moreconservative beneficial.