Time-dependent structural response of reinforced concrete bridge piers considering degradation phenomena uncertainties

Recent studies have shown that building materials are strongly affected by degradation phenomena, which might result in facility collapses or loss of structural integrity and functionality. Regarding reinforced concrete structures, it is well-recognized that reinforcement corrosion is the main cause of deterioration and reduces both load-bearing capacity and ductility. The Italian infrastructure heritage consists mainly of reinforced concrete bridges approaching their lifespan, therefore predictive analyses are required to schedule retrofit interventions. Degradation processes are highly dependent on both weather parameters (e.g. relative humidity and average temperature) and structural detailing, such as the concrete cover thickness. Due to their inherent uncertainties, predictive analyses performed adopting a deterministic approach may lead to unrealistic, too conservative or unconservative evaluation of the structural safety level, respect to the possible different limit states. To address this issue, a detailed evaluation of the time-dependent structural response of a bridge pier was conducted in this work, accounting for the statistical distribution of stochastic parameters in the definition of the degradation scenarios. Performance-decay curves were defined for the first cracking moment, the yielding moment, and the ultimate moment, considering the effects of reinforcement corrosion rate, concrete cracking and creep.