Study On The Temperature Effect Of Large Span Cable-stayed Bridge With High And Low Tower

With the rapid development of modern cities and transportation,the construction of high and low tower cable-stayed bridges is more and more.When bridges are exposed to natural environment for a long time,the temperature will not only affect the normal serviceability limit state of bridge structures,but also will affect the ultimate state and cause collapse.Most scholars at home and abroad have only studied the temperature effect of the combined bridge and the equal high twin towers cable-stayed bridge,and the research on the high and low tower cable-stayed bridges is less.This thesis,taking the high and low tower cable-stayed bridge in Qingxikou river as the engineering background,analyzes its temperature effect in the construction process and the completion state of the bridge.The main contents are as follows:(1)This thesis introduces the characteristics of the high and low tower cable-stayed bridge,the engineering example,the research status of the temperature effect at home and abroad,the heat transfer between bridge structure and outside world,the heat conduction theory,the finite element method of temperature field and temperature effect.(2)Based on the actual engineering,a finite element model of high and low tower cable-stayed bridge is established.The influence of entire temperature difference,sunshine temperature difference and cable beam temperature difference on the bridge in construction is analyzed,mainly from three aspects:(1)The influence of temperature on the cable force,the stress and vertical displacement of girder before and after the side span closure;(2)The influence of temperature on the sensitive positions of the 10# pier at middle span of high tower,the girder and the cable near high tower around construction stages;(3)The influence of temperature on the cable force,girder stress and vertical displacement on both sides of high and low tower when the two sides of the bridge tower are constructed to the same construction stage.(3)After the completion of the high and low tower cable-stayed bridge,the influence of temperature on the girder and the cable of the finished bridge structure is compared and analyzed.