Seismic performance evaluation of fiber-reinforced concrete bridges under near-fault and far-field ground motions

Abstract

The benefit of fiber reinforced concrete (FRC) to the seismic performance of bridges under different earthquake scenarios and damage mechanisms has not been fully addressed. This paper focuses on evaluating the seismic performance of bridge piers considering both flexural and brittle failure mechanisms at different damage states under both far-field and near-fault ground motions by fragility functions. To achieve this goal, 30 near-fault and 30 far-field ground motions were selected for nonlinear time history analysis. Both Cloud Analysis and Incremental Dynamic Analysis (IDA) were employed to establish the relationship between the Engineering Demand Parameter (EDP) and Intensity Measure (IM) for developing the fragility curves of piers. Cloud Analysis was compared by IDA to verify whether it is reliable when using deformation-based and force-based EDPs. Fragility curves were developed for FRC piers reinforced with different fiber types to study the effectiveness of fiber types to improve the seismic performance of bridge piers. The results concluded that the near-fault records increase the seismic demands by about 5% for FRC piers and 10% for RC piers compared to far-field earthquakes. The bridge piers reinforced with polypropylene fibers possess less vulnerability for both flexural and brittle failure mechanisms at different damage states than those reinforced with steel fibers. In addition, Cloud Analysis can provide reliable fragility estimates of bridge piers when using both force-based and deformation-based EDPs.