铁路门式墩非线性时程反应分析研究

Study of Nonlinear Time-history Analysis on Railway Portal Pier

研究目的:门式墩属于典型的钢筋混凝土桥墩,在罕遇地震作用下,应进行非线性时程反应分析。本文以某铁路门式墩为研究对象,通过人工生成地震波,利用纤维塑性铰单元建立Midas非线性有限元计算模型,计算其在罕遇地震波下的动力响应。研究结论:(1)将纤维塑性铰模型用于门式墩这种墩柱轴力的时变较大的结构进行非线性弹塑性地震响应分析是可行的;(2)算例计算结果表明:按照规范规定配置箍筋的情况下,门式墩潜在塑性铰区域均不同程度进入了塑性工作状态,在7度(0.1g)和8度(0.2g)的水准下,延性比的平均值分别为1.60和3.02,在9度(0.4g)的水准下,需将截面配筋率提高至1%,延性比的平均值为4.51,满足规范要求;(3)非线性时程反应分析时,设计人员除了需要关心延性比的数值是否满足规范要求以外,还应特别注意查看塑性铰区域截面的状态,以确保结构不发生倒塌;(4)鉴于非线性时程反应分析的理论和软件越来越成熟,规范宜明确给出分析所需的各种参数,便于技术人员进行准确的应用;(5)本研究成果可用于铁路桥梁抗震设计。

Research purposes： The portal pier belongs to typical reinforced concrete bridge piers, at rarely occurred earthquake action, need to do nonlinear time - history analysis. In this paper, the object of study is a railway portal pier, according to generate artificial seismic wave, using fiber plastic hinge model to establish Midas nonlinear finite element model and calculate its dynamic response of rare seismic wave. Research conclusions：（ 1 ）For nonlinear elastoplastic seismic response analysis of the portal pier , which is a kind of time - varying structure of axial force, adopting the fiber plastic hinge model is feasible ; （2） The calculation results show that, in accordance with the provisions regulating the stirrup case, portal pier potential plastic hinge region in varying degrees enters the plastic state, in 7 （0. lg） and 8 （0.2g） level, the average value of ductility ratio were 1.60 and 3.02, in 9 （0.4g） level, the reinforcement ratio increase to 1% , the average value of the ductility ratio was 4.51 can meet the requirements of specification; （3）For the nonlinear time history response analysis, designers not only need to care about the ductility ratio whether meet the requirements of specification, but also need to pay attention to the state of the plastic hinge region section, to ensure that the structure does not collapse ; （4） The theory and software of nonlinear time - history analysis is more and more mature, the various parameters needed for analysis should be clearly defined in the specification, which is convenient for technical staff to carry out accurate application ; （5） Research results can beused for seismic design of railway bridge.