Reliability assessment of existing RC bridges with spatially-variable pitting corrosion subjected to increasing traffic demand

Bridges are critical for transportation networks. Temporary closures due to poor maintenance may trigger adverse cascading events, affecting economic and societal well-being. Two main factors play a key role in bridge health conditions: ageing and wear-and-tear due to the increasing traffic. This paper proposes a comprehensive framework to quantify the combined phenomena in a holistic approach. The reliability assessment of an existing reinforced concrete bridge subjected to increasing traffic demand and spatially-variable pitting corrosion is investigated. Empirical data are used to develop probabilistic models for cracking initiation, pitting factor, severe cracking, and cover spalling.

Statistical distributions of temperatures from a local meteorological station are used to investigate environmental effects on corrosion initiation. For the traffic, national highway databases are used to model the vehicular flow. Ductile and brittle failure mechanics are considered for the structural capacity assessment. Coupled biaxial bending-axial loading domain is adopted for the ductile structural checks. The shear capacity is assessed through the response limit surface from the modified compression field theory results. Finally, Monte Carlo simulations are performed at intervals of 10 years to derive a time-dependent reliability profile compared against standard thresholds to determine the health conditions of the bridge.