The Study On Temperature Effect And Temperature Fatigue Of The Sunflower Arch Bridge

Due to the obscuring action of longitudinal beam,the temperature distribution and temperature stress under the solar radiation that the sunflower arch bridge shows is different from other bridge does.In addition,as the temperature stress changes repeatedly within a day,it will raise a temperature fatigue effect in the bridge and changes the stress and strain which affects the bridge’s service life.Therefore,it’s necessary to make a research on the temperature effect and temperature of the sunflower bridge.Based on the Second Fenghuang bridge in Guangzhou,Nansha district,the research selects three girders from the main arch and a girder from the longitudinal beam and builds their 2d finite element models to simulate the temperature field.It’s found that the maximum temperature difference of the arch girder on the bottom reach a peak at 10:00 and 16:00,and the temperature stress is greatest also at 10:00.Meanwhile,the closer the girder of the arch stays from the bottom,the greater the temperature difference and temperature effect are.As to the beam girder,the most unfavorable moment is at 14:00,and the influence of the maximum temperature difference and temperature effect of the beam girder is more serious than that of the arch girder.The vertical temperature gradient equation and the law of longitudinal temperature distribution is deduced at the same time.In addition,a test of the temperature field is finished to prove the validity of the simulation.According to the above result,the temperature stress time history curve is used as the load spectrum.And the most unfavorable nodes are selected to make the fatigue analysis based on S-N curve.In addition,the harm that the corrosion and stress concentration does to the structure is also considered.It’s concluded that when analyzing the temperature fatigue of a sunflower arch bridge,it’s necessary to take the beam girder seriously and pay attention to the concrete crack and the corrosion.The residual stain and the constitute relation of concrete of the temperature fatigue has been calculated and compared to that of the live load.As a kind of long-term alternating load,the temperature load can also affect the long-term deformation of the bridge.