Seismic resilience assessment of highway embankments: considering damage measure of hysteretic energy dissipation

Abstract

The wide spatial distribution of highway transportation infrastructure increases its exposure to earthquakes during its service life, thereby raising the risk of damage, particularly for structures with high vulnerability. Therefore, the concept of seismic resilience has attracted extensive attention from academia and the engineering community in recent years. Previous researches on the seismic performance of embankments focused on fragility analysis, and permanent ground displacement (PGD) from field investigations was adopted as a damage measure (DM). However, it cannot explicitly reflect the dynamic response and damage mechanism during earthquakes, and whether it can precisely reflect the damage state (DS) also requires further research. In addition, some preliminary frameworks have been established for the seismic resilience of embankments, but there are no quantitative assessment methods and results. In view of this, a complete framework including hazard analysis, fragility analysis and resilience assessment is proposed to evaluate the seismic resilience of a high-filled embankment. To effectively reflect the damage mechanism of the structure, the DM of hysteretic energy dissipation and corresponding classification criteria of different DSs are established. The dynamic response and damage mechanism of embankments are analyzed through finite element nonlinear dynamic analysis, and the fragility analysis is carried out based on the DM of hysteretic energy dissipation. Ultimately, the resilience of embankments at different seismic scenarios is evaluated by combining the restoration functions under different DSs, and the effects of embankment height and embankment slope gradient are analyzed to effectively guide the seismic design. The results show that at the peak ground acceleration (PGA) of 0.4 g, the resilience of the embankment shows a significant decrease due to the lower robustness and rapidity, and the resilience index decreases to 0.79. The resilience index shows a nonlinear decreasing trend with the increase of embankment height, and the corresponding resilience indexes of the embankments with the heights of 10 m, 15 m, and 20 m are 0.85, 0.83, 0.79 at the PGA of 0.4 g. As the slope gradient is reduced, the resilience of the embankment has a significant enhancement only when the PGA is greater than 0.2 g, and the resilience indexes under the slope gradients of 1:1.75, 1:2, and 1:2.25 are 0.79, 0.82, and 0.83 at the PGA of 0.4 g. The resilience enhancement realized by the slope grading has a significant marginal effect. The framework is an extension of the traditional seismic performance analysis to optimize the pre-disaster seismic design and post-disaster restoration process, which is important to ensure the normal operation of the highway system and reduce the socio-economic costs.