Experimental Study on Seismic Performance of Railway Gravity Bridge Piers with Different Reinforcement Ratios

In order to study the influence of reinforcement ratio on the seismic performance of railway gravity bridge piers, five pier models were designed and manufactured. Low cycle reciprocating loading test was carried out and the failure states of the bridge piers were studied. The influence of reinforcement ratio on the seismic performance of pier was analyzed from the aspects of hysteretic curve, skeleton curve, stiffness degradation, displacement ductility coefficient, energy dissipation capacity and bond-slip between steel bar and concrete. Results show that the reinforcement ratio has a great influence on the response of bridge pier in failure stage. For piers with the reinforcement ratio less than 0.5%, when the piers are damaged, the longitudinal reinforcement is broken. The concrete at the bottom of piers has no obvious spalling, and no obvious plastic zone is formed. The higher the reinforcement ratio is, the fuller the hysteretic curve of the pier is, the higher the horizontal bearing capacity is, the more the accumulated energy consumption is, the greater the stiffness is and the stronger the deformation capacity is under the same loading displacement. After the horizontal load reaches the peak, with the increase of loading displacement, the bearing capacity of piers with the reinforcement ratio less than 0.5% does not decrease significantly, while the bearing capacity of piers with the reinforcement ratio of 1.0% decreases continuously. For railway gravity piers with low reinforcement ratio, the first yield method should be used to calculate the allowable displacement ductility coefficient. The effect of reinforcement ratio on the bond-slip displacement is significant, and the effect decreases gradually with the increase of reinforcement ratio. © 2021, Editorial Department of China Railway Science. All right reserved.