铁路空心墩寒潮作用下温度应力场试验研究

Test Study of Temperature and Stress Fields of Railway Bridge Hollow Piers Under Action of Cold Wave

为改善寒潮作用引起的空心墩外表面混凝土受拉甚至开裂,以新杨家湾特大桥7号墩及牛角坪特大桥3号墩为工程背景进行铁路空心墩在寒潮作用下温度与应力场的试验研究。分别对两桥墩缩尺模型进行试验,采取从内部加热的方法模拟寒潮对桥墩混凝土的作用,并根据试验测得的寒潮温度场,采用有限元软件ANSYS分析桥墩模型相应的寒潮温度应力。模型试验结果与有限元分析结果一致表明:寒潮降温越快,对空心墩墩壁温度场影响深度越浅,桥墩外表面拉应力越大,越有可能造成表面开裂。

To improve the tensile stress or even cracking induced by cold wave in the exterior surface concrete of hollow piers,the Pier No.7 of the New Yangjiawan Bridge and the Pier No.3 of the Niujiaoping Bridge were cited as examples and the test study of temperature and stress fields of railway hollow piers under the action of cold wave was made.The scale-down models of the said two piers were respectively tested,the action of cold wave on the concrete of the piers was simulated by the method of heating inside the piers,the cold wave temperature filed was measured according to the tests and the finite element software ANSYS was then used to analyze the corresponding cold wave temperature and stress of the models.The results of the tests and finite element analysis are agreeable,showing that the faster the temperature fall due to the cold wave is,the shallower the depth of influence of the temperature fall in the walls of the piers is,the greater the tensile stress in the exterior surface concrete of the piers is,the greater the possibility causing the cracking in the concrete is.