Continuous Box Girder Bridge Temperature Field Observation Analysis And Crack Control Study

Prestressed concrete continuous box girder bridge because of its advantages, in recentyears in the highway bridge to a wide range of applications, but in construction and use thephase, found in practical engineering think reliable, no tensile stress of the prestressedconcrete continuous box girder, because of the failure to pay full attention to temperatureeffect and serious crack, and some Bridges even forced repair service, and caused seriouseconomic loss. The temperature distribution of the bridge and the deflection and stress effectcaused by the attention of the bridge experts at home and abroad, the use of differenttemperature gradient model calculated temperature difference in stress box is very big, if thetemperature field distribution of gradient model is wrong, even if the temperature increasedesign value, also can’t guarantee structure not crack, in order to ensure that the bridgestructure of the resistance and good structure performance, should according to localconditions, through the experiment and theory research work, have suitable for the localtemperature field distribution.Combined with a prestressed concrete continuous girder bridge, the concrete girderssunshine of the temperature distribution of time-varying, determine the research area, thevertical temperature gradient curve，then analyzes the structure under different temperaturegradient effect the temperature effect. Through more than a concrete bridge to the seriouscrack damage accident investigation and analysis, give the crack control measures to guidethe construction. The main research contents include the following three aspects：(1) Through the concrete box girder temperature field of the monitoring, the research inthe box under the action of time-varying temperature distribution rule. Comparison of rules ofboth at home and abroad about temperature load relevant provision, established a concretebox girder time-varying temperature gradient model.(2) Using finite element analysis software Midas calculation based on the research of thebridge in temperature gradient under the action of both at home and abroad and the provisionsof the code of the temperature gradient under the action of temperature stress, temperaturegradient model to analyze the different bridge stress and deflection effect.(3) This article unifies the related literature, and analysis the prestressed concretecontinuous box girder bridge the characteristics of temperature and the temperature cracks thecauses of cracks, and then presents prestressed concrete continuous box girder bridgetemperature crack control measures, guide the design and construction of the bridge.