移动热荷载对混凝土槽形梁的影响
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摘要
温度作用是导致桥梁结构在施工与运营期间产生裂缝的重要原因之一,其对桥梁结构的安全性、耐久性和适用性均有显著的影响。由于温度作用的复杂性,在以往的设计中往往采用过度简化的计算模型和方法,导致温度荷载取值和温度应力计算与实际结果存在较大偏差。本文以一64 m简支槽形箱梁为研究对象,结合该桥有铁水罐车通过这一特殊工况,对槽形箱梁的温度效应问题进行了适当的假设和简化,初步探讨了64 m简支槽形箱梁在移动热荷载作用下的温度场和温度应力分布。结果表明:槽形梁的最大应力随铁水罐车通过时间的增长呈线性增长趋势,铁水罐车正常通过桥梁时产生的温度效应对槽形梁的影响极为有限。本文为同类桥梁设计提供了参考建议。
Temperature effect is one of the important reasons causing the cracks on the bridge structure during construction and operation,and it is of significant influence in safety,durability and applicability of the bridge.Because of the complexity of the problem,an overly simplified calculation model and method were used in the existed design, leading to great difference between the calculation and the actual case in terms of temperature load and temperature stress.In this paper,a 64 m-span simply-supported trough girder with passing molten iron tankers was studied.Appropriate assumption and simplification were carried out for the temperature effect of the channel beam.The temperature field and temperature stress distribution under moving radiation heat load on this girder were studied.The results show that the maximum stress of the trough girder linearly increases with the passing time of the molten iron tanker.When molten iron tanker passes through the bridge normally,the temperature effect on channel girder is extremely limited.This research may be used for the design of similar bridges.
Temperature effect is one of the important reasons causing the cracks on the bridge structure during construction and operation,and it is of significant influence in safety,durability and applicability of the bridge.Because of the complexity of the problem,an overly simplified calculation model and method were used in the existed design, leading to great difference between the calculation and the actual case in terms of temperature load and temperature stress.In this paper,a 64 m-span simply-supported trough girder with passing molten iron tankers was studied.Appropriate assumption and simplification were carried out for the temperature effect of the channel beam.The temperature field and temperature stress distribution under moving radiation heat load on this girder were studied.The results show that the maximum stress of the trough girder linearly increases with the passing time of the molten iron tanker.When molten iron tanker passes through the bridge normally,the temperature effect on channel girder is extremely limited.This research may be used for the design of similar bridges.
引文
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[8]戴公连,唐宇,刘勇,等.高铁圆端形空心高墩日照温度场数值分析[J].桥梁建设,2016,46(6):67-72.
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[2]徐丰.混凝土箱梁桥温度效应关键因素研究[D].武汉:华中科技大学,2009.
[3]马如进,崔传杰,马明雷.近塔桥面火灾对三塔悬索桥结构性能影响研究[J].湖南大学学报(自然科学版),2017,44(5):88-95.
[4]李利军,万祥斌,董晓明.大跨径悬索桥缆索承重构件公路火灾的瞬态空间温度场数值模拟[J].合肥工业大学学报(自然科学版),2015,38(5):659-663.
[5]耿旭.复杂结构辐射换热工程应用及数值计算[D].北京:清华大学,1997.
[6]杨贤荣,马庆芳,原庚新,等.辐射换热角系数手册[M].北京:国防工业出版社,1982.
[7]杨永清,叶浪,吴德宝.高低塔斜拉桥在温度作用下的静力特性研究[J].世界桥梁,2017,45(5):26-32.
[8]戴公连,唐宇,刘勇,等.高铁圆端形空心高墩日照温度场数值分析[J].桥梁建设,2016,46(6):67-72.
[9]刘常鹏,徐大勇,张宇,等.铁水装运过程的温降分析[J].冶金能源,2009,28(5):10-12.