青藏高原大跨度铁路连续刚构桥温度效应研究

Study on Temperature Effect of Long-span Continuous Rigid Frame Railway Bridges in Tibetan Plateau

分析大跨度连续桥梁温度应力的影响,以拉日铁路雅鲁藏布江三号特大桥为例进行研究.采用Midas Civil计算软件,对箱型截面的大跨度桥梁成桥后,在温度梯度作用下,对梁体的最大应力进行分析计算.采用Midas FEA计算软件,分析箱型截面冬季施工养护期间,在箱体内部温度和高于外部温度的实测值下,分析单个现浇块体的应力值,为养护温度的设定提供参考依据.计算结果表明:温度对桥梁的应力影响较大,在西藏地区的温度变化快,温度较低的条件下,桥梁的抗裂能力能够满足当地气候条件.冬季施工期间,箱体内外养护温度差较大时会产生拉应力,必须合理的控制内外温度差和拉应力值,保证混凝土养护期间不开裂.

Analysis of the influence of temperature stress in long-span continuous bridge,in order to investigate this issue,take the 3rd Super Bridge of Brahmaputra as an example.Using the Mi-das Civil software to analyse the maximum stress of the the long-span bridge with box section af-ter completing bridge under the effect of the temperature gradient.Using the Midas FEA software to analyse the stress of the individual cast-in-place block,in the condition that the internal meas-ured temperature is higher than the external measured temperature during construction and main-tenance stage in winter,which can provide a reference for the settings of curing temperature.The calculation result shows that temperature has a great influence on the stress of bridge.In the con-dition of rapid temperature change and low temperature in Tibet,the crack resistance of the bridge can meet the local climatic conditions.During construction in winter,there would be tensile stress generated when curing temperature difference is large enough,so it is necessary to control the temperature difference between internal and external reasonable and tensile stress.ensured that the concrete does not crack during maintenance.