A generalized, model-free framework for assessing scour-induced bridge pier instability

• Published in: Engineering structures 2024-06, Vol.309, p.118086, Article 118086
• Main Authors: DeMello, Neandro, Bridge, Jennifer A.
• Format: Article
• Language: English
• Subjects: Bridge pier assessment; Finite-element modeling; Hurricane-induced loading; Local scour assessment
• ISSN: 0141-0296; 1873-7323
• DOI: 10.1016/j.engstruct.2024.118086

Flood-induced scour is one of the leading causes of bridge failures in the United States, accounting for 53 % of recorded failures between 1989 and 2000. With many existing bridges considered “scour critical”, it is essential to closely monitor its development for effective mitigation. However, despite advances in scour hole measurement techniques, continuous monitoring of scour remains underused and little guidance is available to maintenance engineers to assess structural stability from scour depth measurements. This research presents a proof-of-concept, model-free bridge pier structural assessment framework. This framework is built on a library of bridge pier failure surfaces – curves that define failure limits for combinations of scour, wind, and flood loading for a range of structural configurations and site conditions. User input is limited to basic structural and site information, from which a corresponding failure surface is automatically selected, either directly or through interpolation between surfaces in the library. In this study, the creation of a failure surface library and framework is focused on pile bent pier designs, due to their widespread use. A broad scope of parameters was modeled such that common configurations of pier bent bridge designs and site conditions in Florida were considered. Sensitivity studies were performed to identify parameters for which modeling simplifications could be made to build the failure surface library with reduced computational burden. Results from three case study bridges are presented to verify that the resulting assessment framework maintained reasonable representation of structural response. •This research developed a new, model-free assessment framework which uses a library of failure surfaces.•Failure surfaces provide information on the combination of demands which results in failure.•Baseline failure surfaces are generated using simplified finite-element models representative of bridge design practices.•Site-specific failure surface generated from adapting baseline failure surfaces using in-situ soil data.•Results from three case studies demonstrate good agreement between framework-generated and real-bridge failure surfaces.