Seismic fragility analysis for tall pier bridges with rocking foundations

Abstract Costal bridge systems usually contain tall piers with heights over 40 m, due to the engineering site exposed deep water circumstances. Note that conventional seismic isolation devices (e.g., bearings) are not effective for piers, since their dynamic performance is significantly affected by distributed mass and vibration modes of columns; therefore, base design philosophy could be a promising alternative mitigating demands this type bridges. This paper mainly investigates efficiency rocking foundations in improving pier bridges, results presented format fragility curves. Finite element model prototype developed, responses subjected near-fault motions obtained using nonlinear time history analysis. Probability demand models curves then developed accordingly, based on which bridges assessed. The show employment reduce probability being damaged. Before initiation uplifting at base, behavior resembles ones integrated foundation. While initiates under strong excitations, drastically compared tend similar different motions, benefits post-earthquake assessment these