Probabilistic structural performance of RC frames with corroded smooth bars subjected to near- and far-field ground motions

This paper investigates the seismic vulnerability of existing RC frames exposed to corrosion and subjected to near-field and far-field ground motions. A threefold approach for corrosion is adopted to illustrate the probabilistic framework and define time-dependent performance criteria for an accurate seismic fragility assessment. A bond-slip model is employed to simulate the fixed-end rotation and column-beam joints behaviour to account for the deficit in the bond strength of plain rebars. Such a model is calibrated using experimental studies from the literature and considering the effects of corrosion. An inelastic buckling model of steel bars is also incorporated in the finite element model through a hysteretic material to investigate its impact on the deformation capacity of RC members. The effects of near-field and far-field earthquakes are investigated through incremental dynamic analyses (IDA) and cloud analyses on a typical four-storey RC frame with plain bars. Results from the fragility analysis indicate that corrosion has significant effects on the seismic performance of such RC frames over time and near-field pulse-like motions are more destructive than both near-field no-pulse-like and far-field earthquakes.