Performance‐based design method for isolated hollow RC piers with irregularity in height

Abstract

AbstractThe bridge piers are the main components, and their destruction can cause significant damage to bridges. The concentration of failure in one or two piers of irregular bridges has led to challenges in codes and studies regarding the simultaneous failure of the substructure components. The RC hollow sections are structurally adequate for application in isolated bridges with unequal pier heights due to their large strength/mass and stiffness/mass ratios. In the previous studies, the isolation devices have been used to produce uniform lateral stiffness for different pier‐isolator systems of bridges with unequal pier heights. However, this approach leads to the flexural moment concentration in the tall piers and extra ductility demand in the short‐pier isolators. This article presents a new performance‐based design method for isolated hollow RC piers with irregularity in height to provide uniform performance along the bridge. The target performance level is achieved by proper selection of the characteristics of LRBs and pier cross‐sections. This method is used for two continuous span bridges with slight and severe irregularities, and the responses are compared with other design methods. The results show that the proposed method produces similar performance levels in all piers, besides uniform ductility demand, uniform shear strain, and simultaneous failure of all LRBs. Furthermore, the damage probability of tall piers decreases and gets close to that of the short ones.