Research On Temperature Effect Of Concrete Curved Box Girder Bridge In Wuhan City Based On The Measured Data

At present,the temperature effect of concrete straight girder bridge is widely studied,but the related research of concrete curved box girder bridge is relatively rare and not deep enough.A comprehensive analysis platform of TAITherm/Hyper Mesh/ANSYS is built to simulate the temperature field and temperature effect of the ramp of an overpass in Wuhan for the whole year in this paper.Based on the simulation results and the measured results are in good agreement,some characteristics and rules of temperature effect different from that of concrete straight box girder bridges are obtained.The main research work and conclusions of this paper include:(1)This paper makes a model refinement simulation of the temperature field of concrete curved box girder bridge in time and space.The boundary condition simulation of the model can accurately consider many meteorological parameters: solar radiation,temperature,wind,speed,cloud amount,etc.,and establish the boundary conditions of real-time changes of the bridge surface through the measured meteorological data of Wuhan area;(2)To verify and correct temperature field spatio-temporal model of concrete curved box girder bridge,comparing the simulation results with the results of long-term real-time monitoring,modifying the thermophysical parameters and thermal boundary conditions of the simulation model;(3)Through the statistical analysis of measured data,the extreme effective temperature and the most unfavorable temperature gradient of curved box girder bridge in Wuhan area are 37.7 C and 27.4 C.It is found that the most unfavorable temperature gradient inside and outside the curve has different laws: the temperature difference of the inner top web is greater than that of the outer;the temperature difference of the outer bottom web is greater than that of the inner;(4)Sensitivity analysis of various factors affecting temperature distribution shows that radiation wind speed and cloud shelter coefficient have the greatest impact on vertical temperature difference,followed by wind speed and cloud shelter coefficient,and the smallest influence is atmospheric daily temperature difference;(5)The most disadvantageous temperature gradient along and across the bridge can reach 80% and 90% of the most disadvantageous vertical temperature difference when the concrete curved box girder bridge has shield on both sides and above by simulating the temperature field model;(6)Based on the analysis of the measured data of the bridge during the cold wave,it is found that the temperature was reduced by 20 ?within 16 hours,bridge deck temperature decreased by 33?,the temperature difference between the top and web decreases by 35.6?,and the maximum change range of stress at the bottom of the girder reaches 6.5 MPa within 48 hours,but the temperature effect of the bridge is weakened when the cold wave is relatively small;(7)Through the correlation analysis of the measured temperature field data and temperature effect data,it is found that the relative displacement of pier and beam is positively correlated with the effective temperature of beam,and the stress at the bottom of beam is positively correlated with the temperature difference of bottom web.