Study Of Seismic Performance Of Railway Reinforced Concrete Gravity Bridge Pier

Earthquake damage at home and abroad, the piers of the bridge damagecaused by earthquake damage is very common and very serious. Coupled withour earlier construction of the railway bridge pier to use more gravity, seismicdesign considerations for inadequate, and even some of the bridges is notconsidered earthquake. Therefore, the study of the railway pier seismicperformance of gravity and the failure mode analysis of nonlinear seismicresponse of bridge piers, the establishment of pier seismic design methods, areof great theoretical and practical significance.Based on design principles based on the ability, through the elastic-plasticearthquake response analysis method, a systematic analysis of various designparameters on the ductility of the bridge laws, made some valuable results. Themain research and conclusions are as follows:1. In-depth study of the gravity pier failure mode analysis of concrete andsteel stress-strain characteristics and formula, focusing on the pier bendingfailure and shear failure mode, failure mode presented the proposal to determineits formula. 2. Focuses on the theory of gravity pier seismic ductility, systematicexposition of the basic concepts of seismic ductility, ductility seismicsignificance, ductility in seismic resilience curve and ductility of bridge seismicdesign of a simplified theory.3. Gravity to a pier as the prototype, build pier at the end of a single plastichinge there pier finite element analysis model. The use of general-purpose finiteelement analysis software SAP2000, in considering the different axialcompression ratio, reinforcement ratio and volume stirrup ratio and differentsites and different seismic intensity in the case, a lot elastoplastic earthquakeresponse analysis, the following conclusions:（1）With the increase in axial compression ratio of the piers, the piers ofthe yield moment and yield curvature increases, the limits of cross-sectioncurvature decreases, the curvature ductility into a downward concave curve.（2）With the increase in the rate of reinforcement cross-section bridgepiers, bridge piers increased the yield moment, cross-section curvature ductilitydecreases; with stirrup volume ratio increases, the limit of curvature andsectional curvature ductility significantly increased; when reinforcement ratio is constant, the rate increase could pier volume increases linearly with hoopductility of the piers, but when the stirrup when the rate exceeds a critical value,not increase its ductility basic, concrete piers from the core to reach its ultimatecompressive strain and damage into the tension zone reinforcement reaches itsultimate tensile strain and damage.（3）When the bridge superstructure and the piers under the same height,adjust the size of the pier section (ie, changing the pier shear span ratio), canchange the bridge ductility. But the shear span ratio is too small or too large,would lead to reduced structural ductility, energy dissipation capacity variation.（4）With the increase in the quality of the upper structure, the piers of theyield moment, the yield displacement and displacement ductility factor increases.High cross-section in the pier and pier the same circumstances, the results showthat the greater the span of the bridge structure, the displacement ductilitycoefficient.