少筋混凝土重力式桥墩抗震研究现状

我国铁路桥梁普遍采用少筋混凝土重力式桥墩（配筋率<0.5%），现有普通钢筋混凝土结构的延性抗震理论不适用于该类型桥墩。为了促进我国铁路重力式桥墩抗震理论的发展，详细论述了我国少筋混凝土重力式桥墩的研究现状和存在问题。首先，对少筋混凝土重力式桥墩的破坏特征及破坏机理进行了总结；其次，分析了各参数对少筋混凝土重力式桥墩抗震性能的影响；再次，对目前少筋混凝土重力式桥墩的抗震设计方法进行了汇总与分析；最后，对少筋混凝土重力式桥墩的数值分析模型进行了归纳与分析。通过对现有研究的汇总发现:目前对少筋混凝土重力式桥墩的试验研究主要以拟静力方法为主，还缺少振动台试验研究其动力状态下的破坏机理及抗震性能；少筋混凝土重力式桥墩的破坏机理及其与各影响因素之间的定量关系还不明确；已提出的少筋混凝土重力式桥墩的抗震设计方法存在塑性铰区计算不合理等问题，还需要进一步的完善。为少筋混凝土重力式桥墩抗震研究提供了方向。

State-of-the-art review on research for the seismic behavior of concrete gravity piers with low longitudinal reinforcement ratios

Concrete gravity piers with a longitudinal reinforcement ratio less than 0.5%are commonly used in China,while the ductility-based seismic design theory of ordinary reinforced concrete structures is not suitable for this type of bridge pier.To improve the development of seismic design theory of railway gravity piers,the current research status and existing problems of the concrete gravity piers with low reinforcement ratios were summarized in detail.Firstly,the failure characteristics and mechanism of concrete gravity piers with low longitudinal reinforcement ratios were summarized.Secondly,the influence of various parameters on the seismic performance of concrete gravity piers with low reinforcement ratios was analyzed.Thirdly,the seismic design methods of concrete gravity piers with low reinforcement ratios were summarized and analyzed.Finally,the numerical analysis models of gravity piers were compared.The review of existing researches shows that the experimental researches of gravity pier were mainly based on pseudo-static method,and the failure mechanism and seismic performance under dynamic situations were not studied such as by shaking table tests.It is not clear that the quantitative relationship between the failure mechanism and the influencing factors about gravity pier with low reinforcement ratio.The seismic design methods those had been proposed,which had some problems such as irrational calculation of the plastic hinge region,need further improvement.The study provides a direction of seismic research of concrete gravity piers with low reinforcement ratios.