Analysis Of Wind-induced Responses Of Suspension Cast-in-situ Construction Of Rigid Frame Bridge Across River

With the country’s massive investment in transportation infrastructure,the use of transportation development to drive the development and utilization of land along the route is of great significance for improving the level of urbanization.Bridges that span rivers generally have the characteristics of high piers and large spans.With the development of construction technology,continuous rigid frame bridges with high piers and large spans are more and more widely used in river-crossing bridges.Between valleys and rivers,the terrain environment is complex,and the wind field is greatly affected by the terrain,forming the valley wind field effect and the narrow tube effect.During the construction phase,the wind speed of the high-pier bridge between the river valleys increased significantly,and the wind-induced response of the cantilever construction was relatively large.It is necessary to study the wind-induced response of the cantilever construction of the high-pier rigid frame bridge across the river in the complex terrain.This paper takes the Dongxi River Bridge as the research object,uses Fluent software to simulate the terrain wind,and applies it to the Midas bridge model to study the change law of wind-induced response of high pier rigid frame bridge cantilever construction.mainly includes:(1)Apply Global Mapper and Imageware software to establish a three-dimensional topographic model of the Dongxi River Bridge site under different water levels(low water period and high water period),and measure the wind speed at the bridge site.Comparing the measured wind speed with numerical calculations,the results show that the two are in good agreement,and the numerical model built can be used as a basis for studying the topographical wind field.(2)Using Fluent software,based on CFD theory,calculate the design reference wind speed of the main girder of the Dongxi River Bridge under the maximum cantilever state and under different water heights(low water period and high water period).Analyze the wind field of the bridge site,and calculate the static three-component force coefficient of each construction beam section of the bridge and the static three-component force coefficient of the beam section under different angles of attack,extract the cross-sectional wind pressure and flow field distribution diagram,and analyze Factors that affect the magnitude of the coefficient of the static three-component force.(3)Use Midas software to analyze wind-induced response of bridge cantilever construction.The wind loads at different water heights were applied to the numerical model of the bridge to calculate the wind-induced response of the cantilever construction of the box girder sections of the Dongxi River Bridge in the low water period and high water period.Comparing the calculation results of the bridge wind-induced response during the construction stage under different water level heights,it is concluded that in the low water period,the box girder is the most unfavorable condition of the wind-induced response under the maximum cantilever state,and necessary preventive measures need to be taken.