Research on the seismic design method for concrete gravity piers with low longitudinal reinforcement ratio

Research purposes: Concrete gravity piers with low longitudinal reinforcement ratio are extensively used in the high-speed railway in China. Code for seismic design of railway engineering only gives one stage strength 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 with 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 from 0.1%~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 low longitudinal 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. © 2016, Editorial Department of Journal of Railway Engineering Society. All right reserved.