A framework for probabilistic assessment of clear-water scour around bridge piers

Tubaldi, Enrico and Macorini, Lorenzo and Izzuddin, Bassam A. and Manes, Costantino and Laio, Francesco (2017) A framework for probabilistic assessment of clear-water scour around bridge piers. Structural Safety, 69. pp. 11-22. ISSN 0167-4730 (https://doi.org/10.1016/j.strusafe.2017.07.001)

[thumbnail of Tubaldi-etal-SS2017-A-framework-for-probabilistic-assessment-of-clear-water-scour]
Text. Filename: Tubaldi_etal_SS2017_A_framework_for_probabilistic_assessment_of_clear_water_scour.pdf
Accepted Author Manuscript
License: Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 logo

Download (828kB)| Preview


Scouring at the base of bridge piers is the major cause of bridge collapses worldwide. Computing the scour risk of bridge foundations is therefore key for a correct management and allocation of resources for maintenance and scour mitigation works. Existing risk-assessment models compute the vulnerability of bridge foundations to scour by comparing the equilibrium scour depth associated with peak-flow discharges characterized by a given return period (usually of 100–200 years) with the critical foundation depth of the bridge. This approach neglects completely the history-dependent and time-dependent nature of scour. Yet, it is well known that bridge collapses can often be induced by the accumulation of scour during multiple flood events. This study aims at developing a novel probabilistic framework for the computation of bridge-pier vulnerability to scour using a Markovian approach to account for memory effects in scour development. The paper focuses on the case of local pier scour occurring in clear-water conditions whereby cumulative effects are significant, well understood and known to be the cause of recent reported bridge collapses. A simplified numerical example consisting of an idealised bridge pier in a canal is considered to clarify the application of the proposed framework and to shed light on the effects of some assumptions introduced to simplify the probabilistic scour assessment.