The Temperature Field And Thermal Effect Of Steel-concrete Composite Bridges

The study of temperature field and temperature effect is of crucial importance to the safety and durability of steel-concrete composite bridge.To investigate the temperature field and temperature effect of composite bridge,this dissertation carries on extensive researches including model testing,numerical model development,and extreme value analysis of thermal load.The main results and achievements of the research are summarised as follows:(1)A series of thermal tests on composite box girder specimens are carried out,where the specimens are first heated by a painting mechine inside the laboratory and then heated by solar radiation outdoor.The temperature and strain of the specimens are measured by thermal resistance and strain gauges.The temperature distribution patterns under various circumstances are concluded.Three unfavored vertical temperature distribution pattern of composite bridges are proposed.(2)The therotical model for analysing solar temperature field is established and realized on the general FEM platform ABAQUS,where the solar radiation and shading effect is developed through user subroutine UFLUX.The accuracy and reliability of the proposed model is validated by the above thermal tests and test data in the literature.(3)The decomposition of an arbitrary 2D temperature field is derived by the plane-section assumption.Based on the calibrated 2D numerical model,extensive parametric analysis is carried out to find out the effects of season,bridge oritation,geometric dimensions,asphalt pavement,etc.on the temperature field of composite bridges under solar radiation.The most unfavored design parameters of composite bridge under t emperature effect are also determined.(4)To speed up the numerical simulation,a 1D efficient numerical model on the temperature field of composite bridges under solar radiation is developed.The 1D thermal numerical model is programmed on numerical software Matlab.The accuracy and computational efficience is validated by comparing the result to 2D numerical model aforementioned.The simplified formula of the unfavored vertical temperature distribution pattern of composite bridges are also proposed.(5)By introducing the extreme value theory,this paper establishes the computational framework of developing the design thermal load of composite bridge based on regional climate statistics.Under this framework,the 50-year-return temperature loads of composite bridges at the major cities in China are calculated.The zoning map of design thermal load of composite bridge in China is also presented.(6)This paper carries out case study on the thermal effect of typical three-span continuous composite girder bridge and optimize the bearing articulation of the curved composite bridge under thermal effect.