研究目的：对于我国高速铁路广泛采用的少筋混凝土重力式桥墩（配筋率P <0.5% )；《铁路工程抗震设 计规范》仅给出多遇地震下的一阶段强度设计方法，因而缺乏罕遇地震下的抗震验算方法。为此，本文首先 采用拟静力试验探讨少筋混凝土桥墩的抗震性能与纵筋配筋率的关系，然后提出罕遇地震下的抗震验算指 标及验算方法。 研究结论：( 1)少筋混凝土桥墩的抗震性能与纵筋配筋率密切相关，随着配筋率的增加，延性逐步向钢筋 混凝土桥墩过渡；（2)对于配筋率在0.1% ~ 0. 5%之间的混凝土桥墩，抗震设计中应合理考虑其耗能能力，位 移延性系数限值可在1.0 ~4. 8之间线性内插；（3)提出了罕遇地震下少筋混凝土桥墩的单墩非线性分析模 型及简化分析法，为便于设计人员使用，建议采用简化分析法；（4)本研究结果可为罕遇地震下少筋混凝土重 力式桥墩的抗震设计方法提供参考。

Research purposes： Concrete gravity piers with low longitudinal reinforcement ratio are extensively used in the high - speed railway in China. Code for seismic desi^+n of railway engineering only gives one stage strengtii design method under frequent earthquakes，however，it have no checking calculation method under rare earthquakes. In view of that，the relationship between seismic performance of piers wit!i low longitudinal reinforcement ratio and the ratio of longitudinal reinforcement is discussed， and then seismic checking index and checking method are presented in this paper. Research conclusions ：( 1) Seismic performance of piers with low longitudinal reinforcement ratio is closely related to the ratio of longitudinal reinforcement， with the increase of the ratio of reinforcement，the ductility will be gradually transition to the feature of reinforced concrete pier. (2) Concrete pier with longitudinal reinforcement ratio from0.1% ? 0.5% should consider energy dissipation capacity and limited value of displacement ductility factor can be linearly interpolated from 1.0 to 4.8. (3) A nonlinear analysis model and a simplified analysis method for the single pier with lowlongitudinal reinforcement ratio are presented under rare earthquakes. Simplified analysis method is suggested in order to make seismic design easier to engineers. (4) The research results may provide a reference for design method of the concrete gravity type pier with low longitudinal reinforcement ratio under rare earthquakes.