Seismic Fragility Assessment of RC Columns Exposed to the Freeze-Thaw Damage

Freeze-thaw damage is one of the primary causes deteriorating the seismic resistance of reinforced concrete (RC) structures. This paper proposed a freeze-thaw damage deterioration model for C30 concrete, and it can be employed to study the time-varying seismic performance of aging RC columns. Next, this study developed a seismic fragility analysis framework for deteriorating RC columns considering the effect of freeze-thaw damage. Considering the geometric parameters of the case-study bridge, the deterioration characteristics of material, and the uncertainties involved in structural modeling and ground motions, a probabilistic seismic fragility analysis on aging RC columns was conducted. The results indicate that the influence of freeze-thaw damage cannot be ignored in studying the seismic performance of aging RC structures. The seismic fragilities of deteriorating RC columns shown a nonlinear increase trend as the increased of freeze-thaw cycles and severity of the damage state. In the early stage of freeze-thaw cycles, the seismic fragilities of RC columns increased slowly. However, the closer to the later stage of freeze-thaw cycles, the more significant of the increase in the seismic fragilities of the columns.

Automated summary

This paper proposes a freeze-thaw damage deterioration model for C30 concrete, and develops a seismic fragility analysis framework for aging RC columns considering the effect of freeze-thaw damage. The results indicate that freeze-thaw damage has a significant influence on the seismic performance of aging RC structures.