Time-dependent probabilistic capacity degradation assessment of prestressed concrete piles in marine environment

Abstract

As coastal infrastructure systems are continuously exposed to deterioration, it is increasingly crucial to analyse their current and future serviceability performance. This paper investigates effects of chloride corrosion on the lateral force capacity and ductility of a wharf-supporting prestressed concrete marine pile and provides new insights into the state of marine structures. A probabilistically generated finite element modelling approach is developed for piles, which includes discrete concrete pile cross-sectional models connected to steel tendon non-linear elements via a series of non-linear springs that simulate bonding behaviour. Moreover, a prestressed material model is established that incorporates alternate failure modes including stress corrosion cracking and brittle failure to capture chloride-induced pitting corrosion in piles. It is shown that various failure modes cause an overall decrease in the maximum force capacity as piles age. Specifically, the alternate failure modes result in 31 and 56% reductions in the maximum capacity of the pile and associated top pile displacement, respectively, as the age of the pile increases from 25 years to 75 years. The presented methodology and results can greatly assist in decision-making for repair or replacement of wharves and aid in the design of new wharves considering their future performance.

Keywords:

• Marine structures
• prestressed concrete pile
• time-dependent degradation
• chloride deterioration
• probabilistic models
• non-linear finite element analysis