Research on Temperature Effect of Composite Bridge Tower in Zhang-Jing-Gao Yangtze River Bridge Under Solar Radiation
Temperature significantly affects the safety of bridge structures and is usually a controlling factor in the design of composite bridges.To examine the influence of solar temperature on bridge towers and develop a structural design method for a composite bridge,experimental and simulation analyses are conducted in this study considering the steel-box-CFST bridge tower of the Zhangjinggao Yangtze River Bridge.First,the bridge tower structural model is exposed to solar radiation.The temperatures at key positions and interface voids in the concrete-filled steel tubes(CFSTs)are measured.Then,the distribution law and time history of the temperature field are obtained.The experimental temperature results are simulated using a finite element model.As a result,the external steel box protects the internal structure from radiation and avoids interface voids caused by sunshine.The finite element calculation results are consistent with the experimental results,verifying the calculation method of the model.Second,a model of the entire tower is established,and the sunshine trajectory,temperature time history,and temperature distribution of the actual structure on summer and winter solstice days are analyzed.Sensitivity analyses of the two factors are also performed on the temperature difference between the two sides of the section.The results show that the steel box in different directions of the bridge tower heats up with the change in the solar direction in one day,and the internal temperature of the CFSTs is mainly related to the ambient temperature.Third,the temperature gradient mode of the steel box-CFST section is summarized as multilinear lines.Finally,based on the above analysis of the solar temperature effect,some suggestions for composite-structure bridge design are provided herein.