Tower Hydration Heat Control And Three-tower Cable-stayed Bridge Completion State Parameters Sensitivity Analysis

Cable-stayed bridges are one of the most common bridge shapes among long-span bridges.It is mainly composed of tower,beams and stay cables.With the rapid development of society and economy of various countries,the requirements for the span length of bridges is becoming higher and higher.In order to satisfy the needs of current social development,engineers had to increase the number of towers to form a multi-tower cable-stayed bridge in the process of designing cable-stayed bridges.Generally,the main girder of a cable-stayed bridge is made by prestressed concrete structure,steel structure or steel-concrete combined structure,and the cable tower adopts a concrete or steel structure.For multi-tower cable-stayed bridges with concrete tower,the amount of concrete that was used for the tower is very large that it should be consider as a mass concrete.Therefore,engineers need to face the problems related to the complexity of the cable-stayed bridge structure system and also solve the problems related to the early cracking of mass concrete structures.There are many reasons for early cracks in concrete structures.Including the volume change of the concrete,the shrinkage caused by the heat of hydration of the concrete,the construction method and the construction environmental conditions.At present,scholars at home and abroad have conducted a lot of research on the problem of early cracks in concrete structures.Most researches focus on the change in the volume of concrete and the shrinkage caused by the heat of hydration of concrete.At the same time,there are also researches on cable-stayed bridge design theory.However,for multi-tower cable-stayed bridges with concrete tower,the reasons for the early cracks in the concrete of the tower due to the diversity of construction environmental conditions and construction techniques remain to be studied.On the other hand,research on issues related to the construction of multi-tower cable-stayed bridges needs to be carried out.This research takes the Sixth Yangtze River Bridge as the research background.Consider the related issues of multi-tower cable-stayed bridge construction from two perspectives.The specific content is as follows:1.Use the finite element analysis software Midas Civil to simulate the temperature field caused by the early hydration heat of the D-D section of the low tower of the Yangtze River Sixth Bridge under different construction environment temperatures(10/20 ℃).By combining the measured data of the actual project and the results of the finite element analysis model,the temperature field distribution of the cable-stayed bridge tower concrete under the coupling effect of the heat of hydration and the ambient temperature is studied.2.Use Midas Civil to simulate the construction process of the Sixth Yangtze River Bridge.By changing the structural weight coefficient in the model,the influence of the structural weight error on the main girder,stayed cables and the tower of the bridge is analyzed,which provides a reference for the analysis of errors in construction control.3.By changing the system temperature in the finite element analysis model of the construction process of the Sixth Yangtze River Bridge,the influence of environmental temperature errors on the main girder,stay cables and the tower of the completed bridge is analyzed,which provides a reference for the analysis of errors in construction control.4.By changing the initial tension of stayed cables in the finite element analysis model of the Yangtze River Sixth Bridge in the construction process,the sensitivity of the main girder,stayed cables and the tower of the completed bridge to the initial tension errors is analyzed,which provides a reference for the analysis of errors in construction control.