整跨火荷载下PC薄壁多室变宽箱梁桥的变形  

Deformation analysis of pre-stressed concrete multi-cell thin-wall variable width box girders bridge exposed to co-action of fire and load

作　　者：张岗[1] 贺拴海[1] 王翠娟[1] 

机构地区：[1]长安大学交通行业旧桥检测与加固重点实验室,陕西西安710064

出　　处：《长安大学学报（自然科学版）》2011年第2期42-46,共5页Journal of Chang’an University(Natural Science Edition)

基　　金：国家西部交通建设科技项目(2011318812970)

摘　　要：针对火荷载作用下预应力混凝土薄壁多室箱梁桥的变形状况,基于温变模型和材料的热力参数,利用大型空间有限元程序ANSYS分析了三跨火荷载作用下预应力混凝土薄壁多室变宽箱梁桥的变形,研究了三跨受火、单跨加载和三跨受火、多跨加载模式,并分析了各模式三跨跨中最大挠度在单荷载比下随延火时间的变化规律。研究结果表明:整跨受火、单跨加载或多跨加载模式下,中跨跨中挠度在延火前期均下挠,延火后期有返挠和走平趋势;第一跨和第三跨的跨中挠度在整个延火期内随延火时间呈下挠趋势,均大于第二跨跨中挠度,延火前期第一跨跨中的挠度稍大于第三跨跨中的挠度,延火终期以第三跨的挠度值最为显著。三跨挠度值受箱梁的变宽结构形式、火荷载模式影响较大。Being aimed to deformation problem of pre-stressed concrete thin-walled multi-room box girders exposed to co-action of fire and load,on the basis of enthalpy conduction model and thermo-mechanics parameters,the finite element procedure was applied to analyze the deformation of three spans pre-stressed concrete thin-walled multi-room box girders exposed to co-action of fire and load,fire and load model of single span and multi span was studied,the maximum deflection of each span during prior periods and anaphase of extending-fire time was analyzed with variation of single load ratio.The studied results indicate： under condition of the whole span fire and load model of single span or multi span,the deflection of the mid span is down-warping during the fire prophase,and upward and average during the fire anaphase;the deflection of the first and third span is down-warping with extending time during the whole fire time,which it＇s deflection is bigger than the second span＇s;the deflection of the first span is bigger than the deflection of the second span＇s during the prior periods,the deflection of the third span during the telophase is obvious.The deflection is obvious under action of the variation width and fire load model.2 tabs,3 figs,10 refs.

关 键 词：桥梁工程 薄壁箱梁 单荷载比 火荷载 变形 

分 类 号：U44[建筑科学—桥梁与隧道工程]