Probabilistic analysis of a twin deck curved cable-stayed footbridge subjected to multiple inputs and corrosion.

In order to investigate the benefits of Circular Hollow Section (CHS) structural members to a complex cable-stayed footbridge, this paper presents a simulation-based probabilistic assessment of this type of structures when erected in an aggressive environment. The footbridge studied is located in Pescara, Italy, next to the Adriatic sea. We validated a Finite Element (FE) model of this bridge, and then, we performed a probabilistic study. Owing to corrosion during the bridge design life, both general and localized corrosion models capable of evaluating the reduced load bearing section were adopted; and appropriate probability distributions were assigned to input model parameters. Afterwards, the probabilistic evaluation of the bridge deck response was conducted using non-linear simulations based on Monte Carlo Sampling, where the convergence was accelerated by using Latin Hypercube Sampling (LHS). Serviceability limit state for stresses was satisfied for the footbridge service life for both wind and pedestrian loads. However, for the limit states referred to maximum deck deflection and rotation, the probabilities of failure crossed limiting values suggested in Eurocodes. As a result, for the twin deck curved cable-stayed footbridge with CHS members, the probabilistic analysis was able to predict the exceeding time of limit states’ thresholds. Thus, both repair and a retrofit plan within its design lifetime could be set