The Research On Temperature Field And Temperature Effect Of The Multi Cell Concrete-box Girder

There are many researches on the issue of the temperature effects of theconcrete-box girder at home and abroad. But most attention has been paid to thethermal effects of the temperature field of the simple-box single-cell girder.Compared with the simple-box single-cell concrete-box girder, the simple-boxmulti-cell concrete-box girder is wider in width, greater in stiffness, stronger inself-constraint. For the differences of the thermal effects of the temperature field andtemperate gratitude between the simple-box single-cell and simple-box multi-cellconcrete-box girder, further research is needed. According to the project “On theKey Cracking-control Technologies of Typical Concrete Bridge in Hunan HuaitongHighway”, this paper did a research on the simple-box single-cell and simple-boxdouble-cell concrete-box girder of Jiangshi bridge. Three works involved areintroduced as followings:(1) According to the observations on the thermal effects of temperature fieldunder the condition of typical climate(solar radiation and rapid temperature drop)and the calculated results，an expression which is applicable to the plus and minortemperature gradients is suggested in this paper. The measured data show that thetemperature field of the simple-box single-cell concrete-box girder is similar to thesimple-box double-cell concrete-box girder. Under plus temperature gradients, thelateral temperature difference of the concrete bridge girder across from south tonorth of the river is distinct, which shows that the plus temperature gratitude must beconsidered in two dimensions. Besides, the transverse tensile stress is higher thanthe longitudinal tensile stress, which should be paid enough attention. The tensilestress in the concrete-box is high under minus temperature gradients，which can notbe ignored.(2) Based on the measured data，the finite element simulation is taken fortheoretical analysis by Ansys. The simulation result shows high credible degree. Thecalculated results show that under the plus temperature gradients the temperaturegradients can not be considered one-dimensionally for security consideration.Enough attention must be paid to the transverse tensile stress under plus temperaturegradients and the tensile stress under minus temperature gradients.(3) Based on the measured and calculated data, an expression which isapplicable to the plus and minus temperature gradients in Hunan province is suggested in this paper. The calculation and analysis of the thermal effects oftemperature field will further improve the structure design theory of concrete-boxbridge.