Analysis Of Temperature Field And Temperature Effect Of Long Span Basket Type Steel Truss Arch Bridge

Steel has good thermal conductivity and is sensitive to temperature changes.In recent years,there are many construction problems caused by complex temperature effects in the construction of steel bridges.Scholars at home and abroad have done more research on temperature field and temperature effect of concrete bridges,but less on steel bridges.This paper is based on the construction of the Darui Railway Basket Steel Truss Arch Nujiang Bridge.The main research work is as follows:(1)Summarize the basic theory of heat conduction,introduce the finite element analysis method of temperature field and temperature stress in detail,and determine the boundary conditions and initial conditions used to solve the transient temperature field of the steel box girder of the background bridge.(2)According to the natural environment and structural characteristics of the bridge site,the thermal parameters needed for the simulation of the temperature field of the steel box girder of the main bridge of the background bridge are calculated,such as the solar radiation at all times,the comprehensive temperature and the comprehensive heat transfer coefficient.(3)Using ANSYS finite element software platform,the transient temperature field of non-paved steel box girder under sunshine in summer and winter is analyzed.Considering the shadowing effect of flange plate,the corresponding temperature field distribution of box girder at each time is obtained,the variation law of temperature of each part of box girder with time is analyzed,the most disadvantageous moment of vertical temperature gradient of box girder is determined,and the calculation model of temperature gradient is fitted.?(4)Based on the transient temperature field obtained by finite element thermal analysis,the temperature stress and vertical displacement of steel box girder at the most disadvantageous time in summer are calculated and analyzed by sequential coupling method.(5)On the platform of Midas Civil,the gradient temperature effect of the whole bridge is analyzed according to the gradient temperature and the bridge standard temperature,and the whole bridge temperature rise and fall is calculated and analyzed.