罕遇地震下城际铁路连续梁桥延性抗震设计

研究目的:罕遇地震作用下,城际铁路桥梁结构可能进入到弹塑性工作状态,对城际铁路桥梁结构进行弹塑性地震响应分析和延性抗震设计具有重要的工程价值和研究意义。结合大连市金州新区至普湾新区城际铁路工程的设计实例,基于纤维梁柱单元模型的基本原理,建立主桥(25+30+25)m预应力混凝土连续箱梁桥的弹塑性分析模型,采用傅里叶变换和反复迭代法将铁路规范反应谱拟合为地震动时程曲线,进行罕遇地震下桥梁的地震响应分析及桥墩延性抗震设计。研究结论:结果表明:地震激励下,仅制动墩进入到塑性状态,延性系数最大值为3.02,小于规范给定值4.8,抗震验算满足规范要求。本文给出的桥梁弹塑性分析方法和延性抗震设计结果为城际铁路连续梁桥的延性抗震设计提供了一种实用手段和依据。

Seismic Ductility Design for Intercity Railway Continuous Bridge Under Rare Earthouake

Research purposes: The intercity railway bridge could enter into elastic-plastic stage under rare eathquake excitation,it has a significant engineering value and research meaning to do elastic-plastic seismic analysis and dutility design of intercity railway bridge.Taking a Dalian JinPu intercity railway continuous bridge as as the engineering background,based on the principle of fiber beam-column element model,the elasitc-plastic analysis model of(25+30+25) m prestressed concrete continuous box girdger bridge is modeled,the railway code response spectrum has been converted to artificial earthquake time-history curve using fourier transform method.Furtherly,the rare seismic analysis and ductility design is presented. Research conclusions:The results show that only braking pier enter into plastic stage under rare earthquake excitation,the maximum value of ductily coefficient is 3.02,smaller than railway code given value 4.8,meet standard requirements.The seismic elastic-plastic analysis and ductility design method presented provide a practical method and design basis.