【作者】 聂玉东；

【导师】 田石柱； 王宗林；

【作者基本信息】 哈尔滨工业大学 ， 防灾减灾与防护工程， 2013， 博士

【摘要】 温度作用是混凝土箱梁桥发生裂缝的主要原因之一，目前不同国家、不同地区对混凝土箱梁桥的温度梯度模式及取值没有取得共识。东北寒冷地区是我国纬度最高、经度最偏东地区，独特的地理位置造成该区特殊的气候条件：冬季严寒漫长，气温较同纬度其他地区低10℃以上，夏季温热多雨，春季干旱多风，秋季降温急剧。寒冷地区大跨混凝土箱梁桥温度场分布有别于其他地区，温度裂缝对桥梁结构安全性和耐久性危害程度更大，因此开展寒冷地区大跨径混凝土箱梁桥温度场分布及温度效应的研究，确定更加符合寒冷地区实际情况的混凝土箱梁桥温度梯度分布模式，具有非常重要的意义。本文在对寒冷地区混凝土箱梁桥温度场长期观测的基础上，研究大跨径混凝土箱梁桥温度场分布及温度效应特点，确定寒冷地区混凝土箱梁桥的温度梯度分布模式。主要研究内容和成果概括如下：对黑龙江省同时期建设的三座混凝土箱梁桥温度场进行了一年多的连续观测，观测期涵盖主梁施工期及两个月左右的运营期，获得了大量详实可靠的箱梁温度数据。通过对实测温度数据分析得到在太阳辐射升温、环境骤然降温及冬季寒冷环境下大跨混凝土箱梁顶板、底板及腹板温度的分布规律及其随时间变化规律。采用有限元程序ANSYS对箱梁温度场进行了计算，并将计算值和现场实测值进行了对比分析，表明利用有限元程序ANSYS进行箱梁日照温度场分析，可以得到工程上足够精确的结果。根据有限元分析结果对实测的混凝土箱梁温度场分布进行了补充完善。利用前面的有限元模型，适当变换气象条件、材料热工性质、截面形状等参数数值，计算得到混凝土箱梁温度场随太阳辐射强度、大气温度、截面高度、混凝土导热系数及混凝土比热等参数的变化规律。并对公路桥梁经常采用的桥面铺装结构，分升温及降温两种情况，研究了桥面铺装对箱梁温度场的影响。结果表明太阳辐射强度及桥面铺装是影响混凝土箱梁温度场的主要因素。采用二维模型分析依托工程箱梁横向、竖向及纵向温度应力的分布规律。同时采用三维模型及平面杆系程序进行混凝土箱梁温度应力的对比分析，得到采用不同模型计算温度应力的差别。以依托工程6×150m混凝土连续箱梁桥为研究对象，对比分析了不同“规范”的竖向温度梯度模式及混凝土箱梁纵向温度应力。结果表明，在太阳辐射下，箱梁顶板下缘横向拉应力较大；箱梁下缘负温差在截面下缘产生较大的纵向拉应力，在进行桥梁设计时不考虑截面下缘负温差对结构安全不利。通过对齐齐哈尔地区两座大桥实测温度数据的分析，参考有限元计算结果，得到了位于齐齐哈尔滨市的大跨混凝土箱梁桥无桥面铺装时竖向温度梯度模式及箱梁板件温度梯度模式。结合混凝土箱梁日照温度场影响因素及混凝土箱梁温度效应的研究结论，考虑桥梁所处地理纬度、桥梁腹板方位角及桥面铺装的影响，提出了适合于寒冷地区的大跨混凝土箱梁桥竖向温度梯度模式及板件温度梯度模式。更多还原

【Abstract】 Temperature effect is one of the main causes of cracks in concrete box-girderbridge, the temperature gradient mode and value on concrete box-girder did not gainconsensus in different countries and different regions. Northeast cold areas is thehighest latitude and the most easterly longitude area in our country, the uniquegeographical position causes the special climate, winter is cold and long,temperature is10℃lower compared with other parts of same latitude, summer iswarm and rainy, spring is drought and windy, autumn is cool sharp. Temperaturedistribution of large span concrete box-girder bridge in cold areas is different fromother regions, influence of temperature cracks on structure safety and durability isbigger, so research on temperature distribution and temperature effect of long spanbox-girder bridge, in which the temperature gradient mode which is more suitable incold region is determined, has very important significance.In this paper, based on the long term observation of temperature field ofconcrete bridges in cold region, combined with finite element analysis, thetemperature field and temperature effect features of large span concrete box-girderbridge is studied deeply, the temperature gradient mode in cold region is determined,The main research contents and achievements are summed up as follows:The temperature field is observed continuously for more than one year in threelarge span concrete box-girder bridge in Heilongjiang province on the same period,based on the massive measured data, temperature field distribution characteristics inconcrete box-girder, caused by solar radiation and cooling, resulting from wintercold environmen, is analysis in detail.Temperature field of box-girder is calculated using ANSYS program, and thecomparative analysis of calculated value and measured value indicates that thetemperature field which is precise enough in engineering could be got using ANSYSprogram. According to the results of finite element analysis, the measuredtemperature distribution is complemented and perfected.Using the finite element model, transforming parameter values ofmeteorological conditions, the material thermal physical properties and cross sectionshape, temperature field of box-girder is calculated. The rule of temperature fieldchanging with the solar radiation intensity, air temperature, cross section height,coefficient of thermal conductivity, concrete specific heat etc. is obtained. For thepavement which is often used in bridge deck structure, the influence to temperaturefield is researched in cases of heating and cooling. The results showed that theintensity of solar radiation and the deck pavement is the main factor of concrete box girder temperature field.The cross, vertical and longitudinal temperature stress distribution of theproject box-girder is analyzed using2D model. At the same time, temperature stresswere compared using3D model and plane rod system program, and the difference oftemperature stress using different model is got. Using a6x150m continuousbox-girder bridge as the research object, the vertical temperature gradient mode andthe longitudinal temperature stress according to the different regulation is comparedand analyzed. The results show that the transverse tensile stress at lower edge of theroof caused by the sun radiation is bigger, larger longitudinal tensile stress couldbeen caused by negative temperature difference at lower edge of section.Based on the measured data of two bridge in qiqihar area and the results offinite element calculation, a temperature gradient mode which is suitable for qiqihararea is obtained. Combined with the conclusions of the study about the influencefactors of box-girder temperature field and temperature effect of box-girder, atemperature gradient mode which is suitable for cold regions is put forwardconsidering the bridge geographical latitude, bridge web azimuth and deckpavement correction.更多还原