【作者】 梅竹；

【导师】 贾艳敏；

【作者基本信息】 东北林业大学 ， 桥梁与隧道工程， 2011， 硕士

【摘要】 哈尔滨位于北纬44°04’-46°40’之间的高纬度地带,受西伯利亚强大冷空气影响是同纬度各地区中最为寒冷地区。频繁的寒潮使该地区年温差、月温差及日温差均较大。混凝土桥梁浇筑过程中会受到混凝土水化热影响,且暴露于自然环境中而受到日照、季节温度变化、寒潮等气候因素影响,但混凝土本身导热性能较差,因此往往导致混凝土箱梁在横向与竖向均产生较大温差。由温差引起的温度应力有时甚至可以超过活载、恒载产生的应力。由于混凝土的抗拉性能较差,且箱梁壁板的厚度相对较小,因此较易产生混凝土桥梁温度裂缝,影响混凝土的耐久性和安全性。本文以哈尔滨松浦大桥北引桥的单箱双室混凝土箱梁与南引桥的单箱四室混凝土箱梁为对象进行了试验。统计了哈尔滨从试验开始月份算起的一年内的基本气候特征,并分析了气温、风向、风速、寒潮对混凝土箱梁温度场的影响。以混凝土箱梁的实测温度数据为依据,分别分析了在水化热温度、季节温度及日照作用下的单箱双室混凝土箱梁与单箱四室混凝土箱梁的竖向温度分布与横向温度分布的基本规律。总结出了影响混凝土箱梁的水化热过程的一些因素—混凝土箱梁的截面形式、混凝土的入模温度、高纬度地区的低气温及寒潮等。以传热学理论为依据,采用朱伯芳的大体积混凝土水化放热量的复合指数计算公式,应用ABAQUS有限元软件,模拟分析了单箱双室混凝土箱梁在水化热阶段的热传递过程,并对比分析了计算所得温度场与实测温度场,最后得到了组适用于计算混凝土箱梁水化放热量的复合指数表达式系数,提出了一种合理可行的混凝土箱梁水化热温度场的计算方法。更多还原

【Abstract】 The influence by the cold air from Siberia is very powerful to Harbin due to the location of Harbin between 44°04’～46°40’north latitude. So Harbin is the coldest region among the whole area with the same latitude. The frequently cold wave through Harbin leads to a larger annual and month temperature difference, and a larger temperature difference in a day. The large temperature difference in concrete box girder is resulted by the combination of solar radiation, the seasonal temperature difference, the cold wave, the heat of concrete hydration and the concrete’s relatively low thermal conductivity. This large temperature difference creates significant stresses that can be larger than the stresses due to other applied loads and dead loads. For concrete box girders, because of their thin sections and concrete’s low tensile strength, cracking can occurs and the durability of concrete can be reduced.Two concrete box girders consisting of a single box with two cells and a single box with four cells used on Harbin Songpu Bridge were measured in the field. The climate characteristics of a year in Harbin were collected to analyze the influence by them to concrete temperature. The vertical and lateral temperature distributions and thermal stresses in concrete box girders were analyzed using the measured data. Compared to the concrete box girders consisting of a single box with a single cell from other papers, it can be droved that the heat of concrete hydration are influenced by some factors such as the type of the cross section, the setting temperature of concrete, the lower air temperature and the code wave. By consulting the formula for the heat of hydration of mass concrete, the complex exponential function was used to calculate the heat of concrete hydration of concrete box girder. Based on heat transfer theory, ABAQUS program was used to model the heat transfer and determine the temperature distributions in the concrete box girders during concrete setting. The two coefficients in the complex exponential function were determined based on the experimental results, and a feasible method for calculating temperature field was obtained.更多还原