A Comparative Performance-Based Seismic Assessment of Traditional and Enhanced-Performance Bridge Pier Systems

To minimize residual displacements and improve post-earthquake functionality of a bridge, a system is proposed and evaluated in which vertical, unbonded post-tensioning (UBPT) is used to facilitate self-centering of the piers. In addition, a high performance fiber-reinforced cement composite (HPFRCC) material replaces concrete in the hinging regions of the piers. The HPFRCC provides improved damage-tolerance to the system by reducing large cracks and preventing spalling, which in turn prevents longitudinal bar buckling. This study evaluates the dynamic behavior of self-centering bridge piers with and without the use of HPFRCC and assesses quantitatively several benefits of using enhanced-performance systems in seismic regions by comparing them to a bridge with conventional reinforced concrete piers. A formalized performance-based earthquake engineering assessment methodology developed by the Pacific Earthquake Engineering ResearchCenter is used to carry out the comparison.