The Temperature Field Distribution And Control Measures About Temperature Crack Of Long-span Concrete Box Girder In Seasonal Frozen Soil Region

With the rapid development of China’s transportation, especially with the great westerndevelopment and revitalizing the northeastern economic, we need build much more bridgesin the northeastern region. Compared with previous bridges, these new building bridgesneed larger scale and higher technology.For concrete structure, uneven temperature can cause a lot of deflection and stress,which is one of the main reasons to lead to deflection and crack of continuous box girderbridge. Some long-span prestressed concrete box girder in domestic and foreign countriesoften have many cracks in the construction and operation process, which will cause greatharm to the safety of the structure. The temperature difference is large in northeasternregion of our country, so the temperature stress is considered as the main reason whichresults to crack of prestressed concrete bridge. Therefore, it is very necessary to research ontemperature field distribution and control measures about temperature cracks of long-spancontinuous box girder in seasonal frozen region, confirm model of temperature fielddistribution which is suitable to the situation of seasonal frozen region, and master thetemperature stress distribution characteristics of long-span box girder bridge in seasonalfrozen region. All these researches have important theoretical and practical significance forthe safety and durability of bridges.Therefore, based on the temperature data of Fusui Songhua River bridge constructionmonitoring in Heilongjiang Province, this paper research temperature field distribution andcontrol measures about temperature cracks of long-span continuous box girder in seasonalfrozen region. The content and result is as follows:Based on the observation data, I get the temperature variation trend in all positions ofbox girder and temperature gradient under the condition of temperature-rising and coolingdifferently. It can be known that change of temperature of box girder is as the sine curve,and difference of roof is large; web and floor is much small; similar to Chinese code,Vertical temperature mode is nonlinear variation.Through simulation analysis using the finite element program Ansys, we obtain planetemperature field analysis results and confirm temperature field distribution mode aftertheoretical research, selection of calculating parameter.From3D model established by finite element program Bridge KF, we obtain thetemperature stress of concrete box girder. Considered to the difference of some countries’code for temperature gradient distribution model of bridge, this paper calculates temperature stress and deflection using temperature gradient of some countries’ code and practical data,and from analysis it is known that most of the countries is too safe.According to problems of temperature crack in seasonal frozen region and analysis oftemperature stress and deflection, I give some specific temperature crack control measures.