Finite Element Modelling and Seismic Assessment of Hybrid Isolated-Rocking Bridge Columns

Traditional cast-in-place bridge columns are prone to significant structural damage and irreversible displacements when subjected to strong seismic events. To overcome this limitation, this research introduces an advanced hybrid isolated-rocking (HIR) bridge column system, incorporating precast concrete segments with three critical components: (۱) rocking joints at the ends, (۲) energy-absorbing lead rubber bearings (LRBs) at intermediate connections, and (۳) unbonded post-tensioning tendons. Together, these elements create a dual-function mechanism that combines energy dissipation (via LRBs) with self-centering behavior (through post-tensioning), leading to exceptional seismic behavior. A detailed numerical assessment was conducted using rigorously validated ۳D (ABAQUS) and ۲D (OpenSees) finite element simulations. The study implements an iterative displacement-based design approach that directly considers the system's nonlinear response. The behavior of the proposed column was thoroughly examined through both nonlinear quasi-static pushover analysis and dynamic time-history analyses under far-field seismic loading. The modeling process was cross-verified against the available experimental results. The results confirmed the HIR’s outstanding seismic resilience, showing substantial reductions in structural damage alongside negligible permanent deformations at intermediate joints. Remarkably, the system’s performance remains unaffected by vertical ground motion components. These findings establish the HIR column as a high-performance, low-damage solution for bridge construction in earthquake-prone areas, offering significant advantages over traditional cast-in-place designs. The proposed system not only enhances safety but also reduces post-earthquake repair needs, making it a practical and sustainable alternative for modern seismic-resistant infrastructure.

کلیدواژه ها:

Rocking column ، Post-tensioning ، Precast concrete ، Lead-rubber bearing ، HIR column