Study On The Influence Of Creep Effect Of Concrete Slab On The Composite Girder Cable-stayde Bridge With Three-tower Under The Temperature-humidity Changing

AS road grade is increased continuously and construction scale is enlarged, the presents the development of span becoming bigger and bigger,the style enriching as the structure becomes lighter and lighter.Steel-Concrete Composite Girder is the structure style of the integer is formed by the shear connector between the steel beam and the concrete slab considering Taking Load Together.compare to the steel bridge, Composite Girder has the bigger moment of inertia of cross-section by using the steel girder with smaller cross-section,which benefits to reduce the deflection under the live loads.considering the link effect of the shear connector, the concrete slab can confine the compressed flange of the steel girder to enhance the stability of the beam,which gives full play to material strength.the decrease of the the section,s height make the the shape of the structure delicater as well as improve the landscape effect,which help to increase headroom under bridge or decrease bridge elevation.Erqi Yangtze River Bridge is the composite girder cable-stayde bridge with three-tower with the structure style of the integer is formed by the shear connector between the steel beam and the concrete slab considering Taking Load Togeth.beacause of the effect of creep,there will exist interaction force in the cross-section,which lead to internal force redistribution and additional deformation.however,the temperature and relative humidity in the surrounding environment is the inportant factor to influence concrete creep.the higher temperature decrease concrete viscosity and elastic modulus,then creep ratio increases.the lower relative humidity increases the shrinkage to promote drying creep,and at last make the creep increasing.however the present study about creep effect on concrete bridge is focusing on the aspects of a Constant temperature and relative humidity,which ingore the change about various tempertuer and humidity,to lead not reflect the effect the to creep effect on concrete bridge comperhensivly and really.so proving the effect about the change of temperture and relative humidity to creep effect on concrete bridge will bring more important theoretical and actual application value to the structure design, construction and safe operation on concrete bridge.This paper basing on Erqi Yangtze River Bridge establishes spatial structure model using MIDAS/cvill,and carry out finite element simulation analysis;basing on calculation formula of creep in CEB-FIP(90),a creep coefficient computer program considering the change of temperture and relative humidity is written; the deflection and stress changes of composite girder cable-stayed bridge with three-tower is analyzed under the temperature-humidity changing.detailly speaking,the follow aspects is done:1、simulate and calculate the structure deflection, internal force and stress in the whole construction stage of Erqi Yangtze River Bridge,and verify the rationality of the design;2、basing on calculation formula of creep in CEB-FIP(90),a creep coefficient computer program considering the change of temperture and relative humidity is written, the related parameters are inputed and cycled using main program to obtain the creep coefficient in a specific time of loading,furthermore,the calculation of creep coefficient in finite element simulation analysis is realized,so the calculation theory of concrete creep is riched vigorously;3、The whole year in wuhan is divided into four quarters in this paper,and the average value of temperture and relative humidity in each quarter is considered,the deflection and stress changes of composite girder cable-stayed bridge with three-tower is analyzed under the temperature-humidity changing.the result shows that:the deflection of main girders and stress decrease as the humidity increases and increases as the temperature rises. Furthermore, the maximum and minimum of the deflection differ2cm as the temperature changes and differ6cm as the humidity changes.bring more important theoretical and actual application value to the structure design, construction and safe operation on concrete bridge.